<input type="radio" name="singleAnswer" value="0" <s:property value="%{0 in question.userAnswers ? 'checked' : ''}"/>/>对
<input type="radio" name="singleAnswer" value="1" <s:property value="%{1 in question.userAnswers ? 'checked' : ''}"/>/>错
<input type="radio" name="singleAnswer" value="0" <s:property value="%{0 in question.userAnswers ? 'checked' : ''}"/>/>对
<input type="radio" name="singleAnswer" value="1" <s:property value="%{1 in question.userAnswers ? 'checked' : ''}"/>/>错