fixed a bug

src/components/VocabularyStudy.tsx

@@ -619,7 +619,7 @@ const VocabularyStudy: React.FC = () => {
       ));
       setUserAnswer(response.optionToken);
     } catch (error) {
-      message.error(INVALID_CREDENTIAL_MESSAGE);
+      setUserAnswer(option.text);
     }
   };
 
@@ -647,7 +647,10 @@ const VocabularyStudy: React.FC = () => {
       answerSubmittingRef.current = false;
       return;
     }
-    if (testType === 'multiple-choice' && options.length > 0 && options.every(option => option.token !== normalizedUserAnswer)) {
+    const isKnownMultipleChoiceAnswer = options.some(option =>
+      option.token === normalizedUserAnswer || option.text === normalizedUserAnswer
+    );
+    if (testType === 'multiple-choice' && options.length > 0 && !isKnownMultipleChoiceAnswer) {
       answerSubmittingRef.current = false;
       message.warning('请选择一个选项后再提交');
       return;