diff --git a/server/routes/vocabulary.ts b/server/routes/vocabulary.ts
index 0556980..46a8705 100644
--- a/server/routes/vocabulary.ts
+++ b/server/routes/vocabulary.ts
@@ -42,7 +42,11 @@ interface InteractionEventPayload {
   type?: string;
   key?: string;
   inputType?: string;
+  value?: string;
   valueLength?: number;
+  ctrlKey?: boolean;
+  metaKey?: boolean;
+  altKey?: boolean;
   ts?: number;
 }
 
@@ -70,7 +74,9 @@ const WORD_RECORD_MODES: WordRecordModeKey[] = [
 ];
 
 const ATTEMPT_TTL_MS = 30 * 60 * 1000;
-const MIN_SECONDS_PER_QUESTION = Number(process.env.VOCABULARY_MIN_SECONDS_PER_QUESTION || 1);
+const MIN_STUDY_WORD_COUNT = 10;
+const MAX_STUDY_WORD_COUNT = 100;
+const MIN_SECONDS_PER_QUESTION = Number(process.env.VOCABULARY_MIN_SECONDS_PER_QUESTION || 2);
 const MAX_SECONDS_PER_QUESTION = Number(process.env.VOCABULARY_MAX_SECONDS_PER_QUESTION || 10);
 const VOCABULARY_ALLOWED_ORIGINS = (process.env.VOCABULARY_ALLOWED_ORIGINS || 'https://d1kt.cn,http://localhost:3000,http://localhost:3001')
   .split(',')
@@ -78,6 +84,7 @@ const VOCABULARY_ALLOWED_ORIGINS = (process.env.VOCABULARY_ALLOWED_ORIGINS || 'h
   .filter(Boolean);
 const ATTEMPT_SECRET = process.env.VOCABULARY_ATTEMPT_SECRET || config.JWT_SECRET;
 const ANSWER_PROOF_SALT = 'd1ktsalt';
+const INVALID_CREDENTIAL_MESSAGE = '凭证无效，请检查。';
 
 const isVocabularyTestType = (value: unknown): value is VocabularyTestType => {
   return value === 'chinese-to-english' ||
@@ -281,6 +288,60 @@ const summarizeInteractionEvents = (
   };
 };
 
+const buildKeySequenceText = (events: InteractionEventPayload[]): string => {
+  let text = '';
+
+  events.forEach(event => {
+    if (event?.type !== 'keydown' || event.ctrlKey || event.metaKey || event.altKey) return;
+
+    const key = String(event.key ?? '');
+    if (key === 'Backspace') {
+      text = text.slice(0, -1);
+      return;
+    }
+    if (key === 'Spacebar') {
+      text += ' ';
+      return;
+    }
+    if (key.length === 1) {
+      text += key;
+    }
+  });
+
+  return text.slice(0, 500);
+};
+
+const analyzeInputTraceRisk = (
+  events: InteractionEventPayload[],
+  userAnswer: string,
+  testType: VocabularyTestType
+): string[] => {
+  if (testType === 'multiple-choice') return [];
+
+  const flags: string[] = [];
+  const expectedAnswer = normalizeEnglishAnswer(userAnswer);
+  if (!expectedAnswer) return flags;
+
+  const safeEvents = Array.isArray(events) ? events.slice(0, 300) : [];
+  const inputValues = safeEvents
+    .filter(event => event?.type === 'input' && typeof event.value === 'string')
+    .map(event => String(event.value ?? '').slice(0, 500));
+  const lastInputValue = inputValues[inputValues.length - 1];
+
+  if (inputValues.length === 0) {
+    flags.push('missing_input_value_trace');
+  } else if (normalizeEnglishAnswer(lastInputValue) !== expectedAnswer) {
+    flags.push('input_value_mismatch');
+  }
+
+  const keySequence = normalizeEnglishAnswer(buildKeySequenceText(safeEvents));
+  if (keySequence && keySequence !== expectedAnswer) {
+    flags.push('key_sequence_mismatch');
+  }
+
+  return flags;
+};
+
 const analyzeAnswerRisk = (
   durationSeconds: number,
   summary: InteractionSummary,
@@ -288,12 +349,12 @@ const analyzeAnswerRisk = (
 ): string[] => {
   const flags: string[] = [];
 
-  if (durationSeconds < MIN_SECONDS_PER_QUESTION) flags.push('too_fast');
   if (durationSeconds > MAX_SECONDS_PER_QUESTION) flags.push('too_slow');
 
   if (testType === 'multiple-choice') {
     if (summary.pointerCount === 0) flags.push('missing_choice_interaction');
   } else {
+    if (durationSeconds < MIN_SECONDS_PER_QUESTION) flags.push('too_fast');
     if (summary.keyCount === 0) flags.push('missing_key_events');
     if (summary.inputCount === 0) flags.push('missing_input_events');
     if (summary.pasteCount > 0) flags.push('paste_used');
@@ -588,7 +649,7 @@ router.get('/study-words/:wordSetId', authMiddleware, async (req, res) => {
     if (req.query.count) {
       const parsed = parseInt(req.query.count as string, 10);
       if (!isNaN(parsed) && parsed > 0) {
-        targetCount = Math.min(parsed, 100);
+        targetCount = Math.max(MIN_STUDY_WORD_COUNT, Math.min(parsed, MAX_STUDY_WORD_COUNT));
       }
     }
 
@@ -738,24 +799,24 @@ router.post('/test-attempt', authMiddleware, async (req, res) => {
     const userId = req.user?._id;
 
     if (!userId) {
-      return res.status(401).json({ message: '用户信息无效' });
+      return res.status(401).json({ message: INVALID_CREDENTIAL_MESSAGE });
     }
 
     if (!isAllowedVocabularyOrigin(req)) {
-      return res.status(403).json({ message: '测试来源异常，请从官网页面开始测试' });
+      return res.status(403).json({ message: INVALID_CREDENTIAL_MESSAGE });
     }
 
     if (!mongoose.isValidObjectId(wordSetId)) {
-      return res.status(400).json({ message: '单词集ID无效' });
+      return res.status(400).json({ message: INVALID_CREDENTIAL_MESSAGE });
     }
 
     if (!isVocabularyTestType(testType)) {
-      return res.status(400).json({ message: '未知的测试类型' });
+      return res.status(400).json({ message: INVALID_CREDENTIAL_MESSAGE });
     }
 
     const wordSet = await WordSet.findById(wordSetId);
     if (!wordSet) {
-      return res.status(404).json({ message: '未找到单词集' });
+      return res.status(404).json({ message: INVALID_CREDENTIAL_MESSAGE });
     }
 
     let selectedWords: any[] = [];
@@ -763,23 +824,23 @@ router.post('/test-attempt', authMiddleware, async (req, res) => {
 
     if (Array.isArray(wordIds) && wordIds.length > 0) {
       if (wordIds.length > 100) {
-        return res.status(400).json({ message: '单次测试最多100道题' });
+        return res.status(400).json({ message: INVALID_CREDENTIAL_MESSAGE });
       }
 
       if (wordIds.some((id: unknown) => !mongoose.isValidObjectId(id))) {
-        return res.status(400).json({ message: '包含无效单词ID' });
+        return res.status(400).json({ message: INVALID_CREDENTIAL_MESSAGE });
       }
 
       const uniqueWordIds = [...new Set(wordIds.map((id: string) => id.toString()))];
       if (uniqueWordIds.length !== wordIds.length) {
-        return res.status(400).json({ message: '测试单词不能重复' });
+        return res.status(400).json({ message: INVALID_CREDENTIAL_MESSAGE });
       }
 
       const wordMap = new Map<string, any>(allWords.map(word => [getObjectIdString(word), word]));
       selectedWords = uniqueWordIds.map(wordId => wordMap.get(wordId));
 
       if (selectedWords.some(word => !word)) {
-        return res.status(400).json({ message: '测试单词必须属于当前单词集' });
+        return res.status(400).json({ message: INVALID_CREDENTIAL_MESSAGE });
       }
 
       selectedWords = shuffle(selectedWords);
@@ -792,7 +853,7 @@ router.post('/test-attempt', authMiddleware, async (req, res) => {
     }
 
     if (selectedWords.length === 0) {
-      return res.status(400).json({ message: '没有可测试的单词' });
+      return res.status(400).json({ message: INVALID_CREDENTIAL_MESSAGE });
     }
 
     const issuedAt = new Date();
@@ -837,7 +898,7 @@ router.post('/test-attempt', authMiddleware, async (req, res) => {
     });
   } catch (error) {
     console.error('创建测试会话失败:', error);
-    res.status(500).json({ message: '创建测试会话失败' });
+    res.status(500).json({ message: INVALID_CREDENTIAL_MESSAGE });
   }
 });
 
@@ -847,7 +908,7 @@ router.post('/word-record', (req, res, next) => {
   next();
 }, authMiddleware, async (req, res) => {
   return res.status(410).json({
-    message: '单题记录接口已停用，请通过测试会话提交记录'
+    message: INVALID_CREDENTIAL_MESSAGE
   });
 });
 
@@ -858,15 +919,15 @@ router.post('/test-answer', authMiddleware, async (req, res) => {
     const userId = req.user?._id;
 
     if (!userId) {
-      return res.status(401).json({ message: '用户信息无效' });
+      return res.status(401).json({ message: INVALID_CREDENTIAL_MESSAGE });
     }
 
     if (!isAllowedVocabularyOrigin(req)) {
-      return res.status(403).json({ message: '测试来源异常，请从官网页面提交答案' });
+      return res.status(403).json({ message: INVALID_CREDENTIAL_MESSAGE });
     }
 
     if (!mongoose.isValidObjectId(attemptId)) {
-      return res.status(400).json({ message: '测试会话ID无效' });
+      return res.status(400).json({ message: INVALID_CREDENTIAL_MESSAGE });
     }
 
     const attempt = await VocabularyTestAttempt.findOne({
@@ -875,7 +936,7 @@ router.post('/test-answer', authMiddleware, async (req, res) => {
     });
 
     if (!attempt) {
-      return res.status(404).json({ message: '未找到测试会话' });
+      return res.status(404).json({ message: INVALID_CREDENTIAL_MESSAGE });
     }
 
     const attemptAny = attempt as any;
@@ -886,42 +947,42 @@ router.post('/test-answer', authMiddleware, async (req, res) => {
     if (!Number.isFinite(expiresAt.getTime()) || expiresAt.getTime() < now) {
       attemptAny.status = 'expired';
       await attempt.save();
-      return res.status(410).json({ message: '测试会话已过期，请重新开始测试' });
+      return res.status(410).json({ message: INVALID_CREDENTIAL_MESSAGE });
     }
 
     if (attemptAny.status !== 'active') {
-      return res.status(409).json({ message: '测试会话已提交或已失效' });
+      return res.status(409).json({ message: INVALID_CREDENTIAL_MESSAGE });
     }
 
     const token = String(questionToken ?? '');
     const tokenIndex = attemptAny.questionTokens.indexOf(token);
     if (!token || tokenIndex < 0) {
-      return res.status(400).json({ message: '测试答案的题目标识无效' });
+      return res.status(400).json({ message: INVALID_CREDENTIAL_MESSAGE });
     }
 
     const answeredTokens = Array.isArray(attemptAny.answeredQuestionTokens)
       ? attemptAny.answeredQuestionTokens
       : [];
     if (answeredTokens.includes(token)) {
-      return res.status(409).json({ message: '该题已提交，请继续下一题' });
+      return res.status(409).json({ message: INVALID_CREDENTIAL_MESSAGE });
     }
 
     if (tokenIndex !== answeredTokens.length) {
-      return res.status(400).json({ message: '请按题目顺序提交答案' });
+      return res.status(400).json({ message: INVALID_CREDENTIAL_MESSAGE });
     }
 
     const submittedAtMs = Number.parseInt(String(submittedAt), 10);
     if (!Number.isFinite(submittedAtMs)) {
-      return res.status(400).json({ message: '答案提交时间无效' });
+      return res.status(400).json({ message: INVALID_CREDENTIAL_MESSAGE });
     }
 
     if (Math.abs(now - submittedAtMs) > 5 * 60 * 1000) {
-      return res.status(400).json({ message: '答案提交时间异常' });
+      return res.status(400).json({ message: INVALID_CREDENTIAL_MESSAGE });
     }
 
     const wordId = getObjectIdString(attemptAny.questionWordIds[tokenIndex]);
     if (!wordId || !verifyQuestionToken(token, attemptId.toString(), wordId, tokenIndex, issuedAt)) {
-      return res.status(400).json({ message: '测试题目签名无效' });
+      return res.status(400).json({ message: INVALID_CREDENTIAL_MESSAGE });
     }
 
     let normalizedUserAnswer = String(userAnswer ?? '').trim().slice(0, 500);
@@ -930,14 +991,14 @@ router.post('/test-answer', authMiddleware, async (req, res) => {
       const optionTexts = attemptAny.optionTexts?.[tokenIndex] || [];
       const selectedOptionIndex = optionTokens.findIndex((optionToken: string) => safeEqualString(optionToken, normalizedUserAnswer));
       if (selectedOptionIndex < 0) {
-        return res.status(400).json({ message: '选择项凭证无效' });
+        return res.status(400).json({ message: INVALID_CREDENTIAL_MESSAGE });
       }
       normalizedUserAnswer = optionTexts[selectedOptionIndex] || '';
     }
 
     const expectedProof = buildAnswerProof(attemptId.toString(), token, String(userAnswer ?? '').trim().slice(0, 500), submittedAtMs);
     if (!safeEqualString(expectedProof, String(answerProof ?? ''))) {
-      return res.status(400).json({ message: '答案校验失败' });
+      return res.status(400).json({ message: INVALID_CREDENTIAL_MESSAGE });
     }
 
     const questionShownAtMs = tokenIndex === 0
@@ -945,14 +1006,17 @@ router.post('/test-answer', authMiddleware, async (req, res) => {
       : new Date(attemptAny.answers?.[tokenIndex - 1]?.submittedAt || issuedAt).getTime();
     const duration = Math.max(0, (submittedAtMs - questionShownAtMs) / 1000);
     const interactionSummary = summarizeInteractionEvents(interactions, questionShownAtMs);
-    const riskFlags = analyzeAnswerRisk(duration, interactionSummary, attemptAny.testType);
+    const riskFlags = Array.from(new Set([
+      ...analyzeAnswerRisk(duration, interactionSummary, attemptAny.testType),
+      ...analyzeInputTraceRisk(interactions, normalizedUserAnswer, attemptAny.testType)
+    ]));
 
     const word = await Word.findOne({
       _id: wordId,
       wordSet: attemptAny.wordSet
     });
     if (!word) {
-      return res.status(400).json({ message: '测试会话中的单词已不存在' });
+      return res.status(400).json({ message: INVALID_CREDENTIAL_MESSAGE });
     }
 
     const evaluation = evaluateWordAnswer(word, attemptAny.testType, normalizedUserAnswer);
@@ -989,12 +1053,11 @@ router.post('/test-answer', authMiddleware, async (req, res) => {
         answered: attemptAny.answeredQuestionTokens.length,
         total: attemptAny.questionTokens.length,
         finished: attemptAny.answeredQuestionTokens.length === attemptAny.questionTokens.length
-      },
-      riskFlags
+      }
     });
   } catch (error) {
     console.error('提交单题答案失败:', error);
-    res.status(500).json({ message: '提交单题答案失败' });
+    res.status(500).json({ message: INVALID_CREDENTIAL_MESSAGE });
   }
 });
 
@@ -1005,15 +1068,15 @@ router.post('/test-option-token', authMiddleware, async (req, res) => {
     const userId = req.user?._id;
 
     if (!userId) {
-      return res.status(401).json({ message: '用户信息无效' });
+      return res.status(401).json({ message: INVALID_CREDENTIAL_MESSAGE });
     }
 
     if (!isAllowedVocabularyOrigin(req)) {
-      return res.status(403).json({ message: '测试来源异常，请从官网页面选择答案' });
+      return res.status(403).json({ message: INVALID_CREDENTIAL_MESSAGE });
     }
 
     if (!mongoose.isValidObjectId(attemptId)) {
-      return res.status(400).json({ message: '测试会话ID无效' });
+      return res.status(400).json({ message: INVALID_CREDENTIAL_MESSAGE });
     }
 
     const attempt = await VocabularyTestAttempt.findOne({
@@ -1022,40 +1085,40 @@ router.post('/test-option-token', authMiddleware, async (req, res) => {
     });
 
     if (!attempt) {
-      return res.status(404).json({ message: '未找到测试会话' });
+      return res.status(404).json({ message: INVALID_CREDENTIAL_MESSAGE });
     }
 
     const attemptAny = attempt as any;
     if (attemptAny.status !== 'active') {
-      return res.status(409).json({ message: '测试会话已提交或已失效' });
+      return res.status(409).json({ message: INVALID_CREDENTIAL_MESSAGE });
     }
 
     if (attemptAny.testType !== 'multiple-choice') {
-      return res.status(400).json({ message: '当前题型不需要选项凭证' });
+      return res.status(400).json({ message: INVALID_CREDENTIAL_MESSAGE });
     }
 
     const token = String(questionToken ?? '');
     const tokenIndex = attemptAny.questionTokens.indexOf(token);
     if (!token || tokenIndex < 0) {
-      return res.status(400).json({ message: '测试题目标识无效' });
+      return res.status(400).json({ message: INVALID_CREDENTIAL_MESSAGE });
     }
 
     const optionTexts = attemptAny.optionTexts?.[tokenIndex] || [];
     const selectedIndex = optionTexts.findIndex((text: string) => text === String(optionText ?? ''));
     if (selectedIndex < 0) {
-      return res.status(400).json({ message: '选项无效' });
+      return res.status(400).json({ message: INVALID_CREDENTIAL_MESSAGE });
     }
 
     const answeredTokens = Array.isArray(attemptAny.answeredQuestionTokens)
       ? attemptAny.answeredQuestionTokens
       : [];
     if (tokenIndex !== answeredTokens.length) {
-      return res.status(400).json({ message: '请按题目顺序选择答案' });
+      return res.status(400).json({ message: INVALID_CREDENTIAL_MESSAGE });
     }
 
     const optionToken = attemptAny.optionTokens?.[tokenIndex]?.[selectedIndex];
     if (!optionToken) {
-      return res.status(400).json({ message: '选项凭证不存在，请重新开始测试' });
+      return res.status(400).json({ message: INVALID_CREDENTIAL_MESSAGE });
     }
 
     res.json({
@@ -1064,7 +1127,7 @@ router.post('/test-option-token', authMiddleware, async (req, res) => {
     });
   } catch (error) {
     console.error('获取选择项凭证失败:', error);
-    res.status(500).json({ message: '获取选择项凭证失败' });
+    res.status(500).json({ message: INVALID_CREDENTIAL_MESSAGE });
   }
 });
 
@@ -1075,15 +1138,15 @@ router.post('/test-record', authMiddleware, async (req, res) => {
     const userId = req.user?._id;
 
     if (!userId) {
-      return res.status(401).json({ message: '用户信息无效' });
+      return res.status(401).json({ message: INVALID_CREDENTIAL_MESSAGE });
     }
 
     if (!isAllowedVocabularyOrigin(req)) {
-      return res.status(403).json({ message: '测试来源异常，请从官网页面完成测试' });
+      return res.status(403).json({ message: INVALID_CREDENTIAL_MESSAGE });
     }
 
     if (!mongoose.isValidObjectId(attemptId)) {
-      return res.status(400).json({ message: '测试会话ID无效' });
+      return res.status(400).json({ message: INVALID_CREDENTIAL_MESSAGE });
     }
 
     const attempt = await VocabularyTestAttempt.findOne({
@@ -1092,7 +1155,7 @@ router.post('/test-record', authMiddleware, async (req, res) => {
     });
 
     if (!attempt) {
-      return res.status(404).json({ message: '未找到测试会话' });
+      return res.status(404).json({ message: INVALID_CREDENTIAL_MESSAGE });
     }
 
     const attemptAny = attempt as any;
@@ -1103,29 +1166,32 @@ router.post('/test-record', authMiddleware, async (req, res) => {
     if (!Number.isFinite(expiresAt.getTime()) || expiresAt.getTime() < now) {
       attemptAny.status = 'expired';
       await attempt.save();
-      return res.status(410).json({ message: '测试会话已过期，请重新开始测试' });
+      return res.status(410).json({ message: INVALID_CREDENTIAL_MESSAGE });
     }
 
     if (attemptAny.status !== 'active') {
-      return res.status(409).json({ message: '测试会话已提交或已失效' });
+      return res.status(409).json({ message: INVALID_CREDENTIAL_MESSAGE });
     }
 
     const submittedAnswers = Array.isArray(attemptAny.answers) ? attemptAny.answers : [];
     if (submittedAnswers.length !== attemptAny.questionTokens.length) {
-      return res.status(400).json({ message: '请完成所有题目后再保存测试记录' });
+      return res.status(400).json({ message: INVALID_CREDENTIAL_MESSAGE });
     }
 
     const lastSubmittedAtMs = Math.max(...submittedAnswers.map((item: any) => new Date(item.submittedAt).getTime()));
-    const elapsedSeconds = Math.max(0, (lastSubmittedAtMs - issuedAt.getTime()) / 1000);
-    const minimumSeconds = Math.max(2, attemptAny.questionTokens.length * MIN_SECONDS_PER_QUESTION);
-    if (elapsedSeconds < minimumSeconds) {
-      return res.status(400).json({ message: '答题速度异常，请重新作答' });
+    const isMultipleChoiceAttempt = attemptAny.testType === 'multiple-choice';
+    if (!isMultipleChoiceAttempt) {
+      const elapsedSeconds = Math.max(0, (lastSubmittedAtMs - issuedAt.getTime()) / 1000);
+      const minimumSeconds = Math.max(2, attemptAny.questionTokens.length * MIN_SECONDS_PER_QUESTION);
+      if (elapsedSeconds < minimumSeconds) {
+        return res.status(400).json({ message: INVALID_CREDENTIAL_MESSAGE });
+      }
     }
 
-    const batchRiskFlags = analyzeBatchRisk(attemptAny.answerDurations || []);
+    const batchRiskFlags = isMultipleChoiceAttempt ? [] : analyzeBatchRisk(attemptAny.answerDurations || []);
     attemptAny.riskFlags = Array.from(new Set([...(attemptAny.riskFlags || []), ...batchRiskFlags]));
     const shouldInvalidateBatch = batchRiskFlags.length > 0 ||
-      ['too_fast', 'too_slow'].some(flag => (attemptAny.riskFlags || []).includes(flag));
+      ['too_fast', 'too_slow', 'missing_input_value_trace', 'input_value_mismatch'].some(flag => (attemptAny.riskFlags || []).includes(flag));
 
     const claimedAttempt = await VocabularyTestAttempt.findOneAndUpdate(
       { _id: attempt._id, user: userId, status: 'active' },
@@ -1134,7 +1200,7 @@ router.post('/test-record', authMiddleware, async (req, res) => {
     );
 
     if (!claimedAttempt) {
-      return res.status(409).json({ message: '测试会话已提交或已失效' });
+      return res.status(409).json({ message: INVALID_CREDENTIAL_MESSAGE });
     }
 
     const submittedWordIds = submittedAnswers.map((item: any) => getObjectIdString(item.word));
@@ -1187,7 +1253,7 @@ router.post('/test-record', authMiddleware, async (req, res) => {
     });
 
     res.status(201).json({
-      message: shouldInvalidateBatch ? '测试行为异常，本次记录已保存但不计入掌握' : '测试记录已保存',
+      message: shouldInvalidateBatch ? INVALID_CREDENTIAL_MESSAGE : '测试记录已保存',
       attemptId: attempt._id.toString(),
       stats: verifiedStats,
       results: submittedAnswers.map((result: any) => ({
@@ -1198,12 +1264,11 @@ router.post('/test-record', authMiddleware, async (req, res) => {
         isCorrect: shouldInvalidateBatch ? false : result.isCorrect
       })),
       submittedAt: new Date(lastSubmittedAtMs),
-      riskFlags: attemptAny.riskFlags || [],
       invalidated: shouldInvalidateBatch
     });
   } catch (error) {
     console.error('保存测试记录失败:', error);
-    res.status(500).json({ message: '保存测试记录失败' });
+    res.status(500).json({ message: INVALID_CREDENTIAL_MESSAGE });
   }
 });
 
diff --git a/src/components/VocabularyStudy.tsx b/src/components/VocabularyStudy.tsx
index 7c05ee6..ad8864d 100644
--- a/src/components/VocabularyStudy.tsx
+++ b/src/components/VocabularyStudy.tsx
@@ -78,7 +78,11 @@ interface InteractionEventPayload {
   ts: number;
   key?: string;
   inputType?: string;
+  value?: string;
   valueLength?: number;
+  ctrlKey?: boolean;
+  metaKey?: boolean;
+  altKey?: boolean;
 }
 
 interface NativeInputLikeEvent extends Event {
@@ -110,7 +114,6 @@ interface SavedVocabularyTestRecordResponse {
     duration: number;
   };
   results: TestResult[];
-  riskFlags?: string[];
   invalidated?: boolean;
 }
 
@@ -129,7 +132,6 @@ interface SubmitAnswerResponse {
     total: number;
     finished: boolean;
   };
-  riskFlags?: string[];
 }
 
 interface OptionTokenResponse {
@@ -138,6 +140,9 @@ interface OptionTokenResponse {
 }
 
 const ANSWER_PROOF_SALT = 'd1ktsalt';
+const INVALID_CREDENTIAL_MESSAGE = '凭证无效，请检查。';
+const MIN_STUDY_WORD_COUNT = 10;
+const MAX_STUDY_WORD_COUNT = 100;
 
 const VocabularyStudy: React.FC = () => {
   const navigate = useNavigate();
@@ -165,7 +170,6 @@ const VocabularyStudy: React.FC = () => {
   const [pendingAnswers, setPendingAnswers] = useState<PendingAnswer[]>([]);
   const [testAttemptLoading, setTestAttemptLoading] = useState(false);
   const [options, setOptions] = useState<TestOption[]>([]);
-  const [testRiskFlags, setTestRiskFlags] = useState<string[]>([]);
   const [isModalVisible, setIsModalVisible] = useState(false);
   const timeOffsetRef = useRef<number>(0);
   const [timer, setTimer] = useState<NodeJS.Timeout | null>(null);
@@ -332,7 +336,7 @@ const VocabularyStudy: React.FC = () => {
   // 处理单词数量变更
   const handleWordCountChange = (value: number | null) => {
     if (value !== null) {
-      setWordCount(value);
+      setWordCount(Math.max(MIN_STUDY_WORD_COUNT, Math.min(value, MAX_STUDY_WORD_COUNT)));
     }
   };
 
@@ -495,7 +499,6 @@ const VocabularyStudy: React.FC = () => {
       setTestResults([]);
       setPendingAnswers([]);
       setOptions(normalizeOptions(questions[0]));
-      setTestRiskFlags([]);
       resetInteractionTrace();
       setIsModalVisible(false);
       setStudyStats({
@@ -506,11 +509,7 @@ const VocabularyStudy: React.FC = () => {
         duration: 0
       });
     } catch (error) {
-      if (error instanceof ApiError) {
-        message.error(`创建测试会话失败: ${error.message}`);
-      } else {
-        message.error('创建测试会话失败');
-      }
+      message.error(INVALID_CREDENTIAL_MESSAGE);
     } finally {
       setTestAttemptLoading(false);
     }
@@ -558,6 +557,40 @@ const VocabularyStudy: React.FC = () => {
     ].slice(-300);
   };
 
+  const getTestInputElement = (): HTMLInputElement | null => {
+    return inputRef.current?.input || null;
+  };
+
+  const moveTestInputCaretToEnd = () => {
+    window.setTimeout(() => {
+      const input = getTestInputElement();
+      if (!input) return;
+      const end = input.value.length;
+      input.setSelectionRange(end, end);
+    }, 0);
+  };
+
+  const focusTestInputAtEnd = () => {
+    inputRef.current?.focus?.();
+    moveTestInputCaretToEnd();
+  };
+
+  const shouldBlockInputKey = (event: React.KeyboardEvent<HTMLInputElement>): boolean => {
+    const input = event.currentTarget;
+    const selectionStart = input.selectionStart ?? input.value.length;
+    const selectionEnd = input.selectionEnd ?? input.value.length;
+    const hasSelection = selectionStart !== selectionEnd;
+    const caretAtEnd = selectionStart === input.value.length && selectionEnd === input.value.length;
+    const navigationKeys = ['ArrowLeft', 'ArrowRight', 'ArrowUp', 'ArrowDown', 'Home', 'End'];
+    const shortcutKey = event.key.toLowerCase();
+
+    if (navigationKeys.includes(event.key) || event.key === 'Delete') return true;
+    if ((event.ctrlKey || event.metaKey) && ['a', 'x', 'v', 'z', 'y'].includes(shortcutKey)) return true;
+    if (event.key === 'Backspace') return hasSelection || !caretAtEnd;
+
+    return false;
+  };
+
   const handleMultipleChoiceChange = async (option: TestOption) => {
     const currentQuestion = testWords[testIndex];
     if (!currentQuestion || !testAttemptId || showAnswer) return;
@@ -586,11 +619,7 @@ const VocabularyStudy: React.FC = () => {
       ));
       setUserAnswer(response.optionToken);
     } catch (error) {
-      if (error instanceof ApiError) {
-        message.error(`获取选项凭证失败: ${error.message}`);
-      } else {
-        message.error('获取选项凭证失败');
-      }
+      message.error(INVALID_CREDENTIAL_MESSAGE);
     }
   };
 
@@ -653,7 +682,6 @@ const VocabularyStudy: React.FC = () => {
 
       setPendingAnswers(updatedPendingAnswers);
       setTestResults(prev => [...prev, response.result]);
-      setTestRiskFlags(prev => Array.from(new Set([...prev, ...(response.riskFlags || [])])));
       setShowAnswer(true);
       setUserAnswer('');
 
@@ -679,11 +707,7 @@ const VocabularyStudy: React.FC = () => {
       }, 1500);
     } catch (error) {
       answerSubmittingRef.current = false;
-      if (error instanceof ApiError) {
-        message.error(`提交答案失败: ${error.message}`);
-      } else {
-        message.error('提交答案失败');
-      }
+      message.error(INVALID_CREDENTIAL_MESSAGE);
     }
   };
 
@@ -712,24 +736,19 @@ const VocabularyStudy: React.FC = () => {
         duration: savedRecord.stats.duration
       });
       setTestResults(savedRecord.results);
-      setTestRiskFlags(savedRecord.riskFlags || []);
       setPendingAnswers([]);
       setTestAttemptId('');
       setShowAnswer(false);
       setTestFinished(true);
       
       if (savedRecord.invalidated) {
-        message.warning('测试行为异常，本次不计入掌握');
+        message.error(INVALID_CREDENTIAL_MESSAGE);
       } else {
         message.success('测试完成，记录已保存');
       }
       setIsModalVisible(true);
     } catch (error) {
-      if (error instanceof ApiError) {
-        message.error(`保存测试记录失败: ${error.message}`);
-      } else {
-        message.error('保存测试记录失败');
-      }
+      message.error(INVALID_CREDENTIAL_MESSAGE);
     }
   };
 
@@ -751,7 +770,6 @@ const VocabularyStudy: React.FC = () => {
     setTestResults([]);
     setPendingAnswers([]);
     setOptions([]);
-    setTestRiskFlags([]);
     interactionsRef.current = [];
     questionShownAtRef.current = 0;
     answerSubmittingRef.current = false;
@@ -973,14 +991,14 @@ const VocabularyStudy: React.FC = () => {
 
                 <h4>学习单词数量:</h4>
                 <InputNumber
-                  min={5}
-                  max={100}
+                  min={MIN_STUDY_WORD_COUNT}
+                  max={MAX_STUDY_WORD_COUNT}
                   value={wordCount}
                   onChange={handleWordCountChange}
                   style={{ width: 120 }}
                 />
                 <span style={{ marginLeft: 10, color: '#888' }}>
-                  (范围: 5-100个单词)
+                  (范围: {MIN_STUDY_WORD_COUNT}-{MAX_STUDY_WORD_COUNT}个单词)
                 </span>
               </div>
 
@@ -1267,19 +1285,6 @@ const VocabularyStudy: React.FC = () => {
                 />
                 
                 <div style={{ margin: '20px 0' }}>
-                  {testRiskFlags.length > 0 && (
-                    <div style={{
-                      marginBottom: 12,
-                      padding: '8px 10px',
-                      border: '1px solid #faad14',
-                      borderRadius: 4,
-                      color: '#ad6800',
-                      background: '#fffbe6'
-                    }}>
-                      本次测试存在异常交互信号，请按正常节奏作答
-                    </div>
-                  )}
-
                   {testType === 'chinese-to-english' && (
                     <div style={{ fontSize: 24, marginBottom: 15, textAlign: 'center' }}>
                       <div style={{ color: '#666', fontSize: '0.8em', marginBottom: 5 }}>请输入对应的英文单词</div>
@@ -1366,21 +1371,44 @@ const VocabularyStudy: React.FC = () => {
                         recordInteraction({
                           type: 'input',
                           inputType: (e.nativeEvent as NativeInputLikeEvent)?.inputType,
+                          value: e.target.value,
                           valueLength: e.target.value.length
                         });
                         setUserAnswer(e.target.value);
+                        moveTestInputCaretToEnd();
                       }}
                       onKeyDown={e => {
                         recordInteraction({
                           type: 'keydown',
                           key: e.key,
-                          valueLength: userAnswer.length
+                          value: userAnswer,
+                          valueLength: userAnswer.length,
+                          ctrlKey: e.ctrlKey,
+                          metaKey: e.metaKey,
+                          altKey: e.altKey
                         });
+                        if (shouldBlockInputKey(e)) {
+                          e.preventDefault();
+                          moveTestInputCaretToEnd();
+                        }
+                      }}
+                      onFocus={() => {
+                        recordInteraction({ type: 'focus', valueLength: userAnswer.length });
+                        moveTestInputCaretToEnd();
                       }}
-                      onFocus={() => recordInteraction({ type: 'focus', valueLength: userAnswer.length })}
                       onBlur={() => recordInteraction({ type: 'blur', valueLength: userAnswer.length })}
+                      onMouseDown={e => {
+                        e.preventDefault();
+                        focusTestInputAtEnd();
+                      }}
+                      onMouseUp={moveTestInputCaretToEnd}
+                      onSelect={moveTestInputCaretToEnd}
+                      onKeyUp={moveTestInputCaretToEnd}
+                      onContextMenu={e => e.preventDefault()}
+                      onCut={e => e.preventDefault()}
+                      onDrop={e => e.preventDefault()}
                       disabled={showAnswer}
-                      style={{ marginBottom: 15 }}
+                      style={{ marginBottom: 15, userSelect: 'none', WebkitUserSelect: 'none' }}
                       onPressEnter={e => {
                         e.stopPropagation();
                         submitAnswer();
@@ -1388,7 +1416,7 @@ const VocabularyStudy: React.FC = () => {
                       autoFocus
                       size="large"
                       onPaste={e => {
-                        recordInteraction({ type: 'paste', valueLength: userAnswer.length });
+                        recordInteraction({ type: 'paste', value: userAnswer, valueLength: userAnswer.length });
                         e.preventDefault();
                       }}
                     />