diff --git a/app/controllers/files_controller.rb b/app/controllers/files_controller.rb
index 2cfa61cc9..bcfed25dd 100644
--- a/app/controllers/files_controller.rb
+++ b/app/controllers/files_controller.rb
@@ -260,7 +260,12 @@ class FilesController < ApplicationController
 
     return normal_status(-2, "该课程下没有id为 #{params[:id]}的资源") if @file.nil?
     return normal_status(403, "您没有权限进行该操作") if @user != @file.author && !@user.teacher_of_course?(@course) && !@file.public?
-
+    @is_pdf = false
+    file_content_type = @file.content_type
+    file_ext_type = File.extname(@file.filename).strip.downcase[1..-1]
+    if (file_content_type.present? && file_content_type.downcase.include?("pdf")) || (file_ext_type.present? && file_ext_type.include?("pdf"))
+      @is_pdf = true
+    end
     @attachment_histories = @file.attachment_histories
   end
 
diff --git a/app/views/files/histories.json.jbuilder b/app/views/files/histories.json.jbuilder
index f30cf6b1b..9dfec4fd4 100644
--- a/app/views/files/histories.json.jbuilder
+++ b/app/views/files/histories.json.jbuilder
@@ -1,2 +1,3 @@
+json.is_pdf @is_pdf
 json.partial! 'attachments/attachment_small', attachment: @file
 json.partial! "attachment_histories/list", attachment_histories: @attachment_histories
diff --git a/public/react/src/modules/courses/exercise/ExerciseReviewAndAnswer.js b/public/react/src/modules/courses/exercise/ExerciseReviewAndAnswer.js
index c2c9b7bcf..91ca19e7d 100644
--- a/public/react/src/modules/courses/exercise/ExerciseReviewAndAnswer.js
+++ b/public/react/src/modules/courses/exercise/ExerciseReviewAndAnswer.js
@@ -336,6 +336,16 @@ class ExerciseReviewAndAnswer extends Component{
     
   }
 
+  // 选择题，切换答案
+  changeOption = (index,ids) =>{
+    //console.log(index+"    "+ids);
+    this.setState(
+      (prevState) => ({ 
+        exercise_questions : update(prevState.exercise_questions, {[index]: { user_answer: {$set: ids} }}),
+      })
+    )
+  }
+
   //简答题 显示和隐藏答案
   changeA_flag=(index,status)=>{
     this.setState(
@@ -726,6 +736,7 @@ class ExerciseReviewAndAnswer extends Component{
                         exercise={exercise}
                         questionType={item}
                         user_exercise_status={user_exercise_status}
+                        changeOption={(index,ids)=>this.changeOption(index,ids)}
                         changeQuestionStatus={(No,flag)=>this.changeQuestionStatus(No,flag)}
                         index={key}
                         ></Single>
@@ -739,6 +750,7 @@ class ExerciseReviewAndAnswer extends Component{
                           exercise={exercise}
                           questionType={item}
                           user_exercise_status={user_exercise_status}
+                          changeOption={(index,ids)=>this.changeOption(index,ids)}
                           changeQuestionStatus={(No,flag)=>this.changeQuestionStatus(No,flag)}
                           index={key}
 
diff --git a/public/react/src/modules/courses/exercise/Testpapersettinghomepage.js b/public/react/src/modules/courses/exercise/Testpapersettinghomepage.js
index bcc0d85a3..65e48962a 100644
--- a/public/react/src/modules/courses/exercise/Testpapersettinghomepage.js
+++ b/public/react/src/modules/courses/exercise/Testpapersettinghomepage.js
@@ -163,6 +163,10 @@ class Testpapersettinghomepage extends Component{
 		}
 
 	}
+    //打开pdf
+	 confpdf = (url) =>{
+		 window.open(url);
+	 }
     /// 确认是否下载
         confirmysl(url,child){
 					let params ={}
@@ -372,7 +376,7 @@ class Testpapersettinghomepage extends Component{
                                     导出<i className="iconfont icon-xiajiantou font-12 ml2"></i>
                                     <ul className="drop_down_menu" style={{"right":"-34px","left":"unset","height":"auto"}}>
                                         <li><a onClick={()=>this.confirmysl(`/exercises/${this.props.match.params.Id}/exercise_lists.xlsx`,this.child)}>学生成绩</a></li>
-                                        <li><a onClick={()=>this.confirmysl(`/exercises/${this.props.match.params.Id}/export_exercise`,this.child)} >空白试卷</a></li>
+                                        <li><a onClick={()=>this.confpdf(`/api/exercises/${this.props.match.params.Id}/export_exercise`)} >空白试卷</a></li>
                                         {/*<li><a onClick={()=>this.confirmysl(`/zip/export_exercises?exercise_id=${this.props.match.params.Id}${this.state.groupyslsval===null||this.state.groupyslsval===undefined?null:this.state.groupyslsval}`)}>学生答题试卷</a></li>*/}
                                     </ul>
                                 </li></Spin>:""}
diff --git a/public/react/src/modules/courses/exercise/question/multiple.js b/public/react/src/modules/courses/exercise/question/multiple.js
index 7e96f8550..bbbfa0c94 100644
--- a/public/react/src/modules/courses/exercise/question/multiple.js
+++ b/public/react/src/modules/courses/exercise/question/multiple.js
@@ -15,6 +15,7 @@ class Multiple extends Component{
   saveId=(value)=>{
     let question_id=this.props.questionType.question_id;
     let url=`/exercise_questions/${question_id}/exercise_answers.json`;
+    let {index}=this.props;
     axios.post((url),{
       exercise_choice_id:value
     }).then((result)=>{
@@ -25,6 +26,7 @@ class Multiple extends Component{
         }else{
           k=0;
         }
+        this.props.changeOption && this.props.changeOption(index,value);
         this.props.changeQuestionStatus && this.props.changeQuestionStatus(parseInt(this.props.questionType.q_position)-1,k);
       }
     }).catch((error)=>{
@@ -42,14 +44,14 @@ class Multiple extends Component{
     console.log(questionType);
     return(
       <div className="pl30 pr30 singleDisplay">
-        <Checkbox.Group disabled={ user_exercise_status == 1 ? true : false } onChange={this.saveId} defaultValue={questionType.user_answer}>
+        <Checkbox.Group disabled={ user_exercise_status == 1 ? true : false } onChange={this.saveId} value={questionType.user_answer}>
           {
             questionType.question_choices && questionType.question_choices.map((item,key)=>{
               let prefix = `${tagArray[key]}.`
 
               return(
                 <p className="clearfix mb15 df">
-                  <Checkbox className="fl lineh-20 " value={item.choice_id}>{prefix}</Checkbox>
+                  <Checkbox className="fl lineh-15 df mr8 mt2" value={item.choice_id}>{prefix}</Checkbox>
                   {/* <span class="fl lineh-20 mt1"></span> */}
                   {/* <span style={{display:"inline-block"}} className="markdown-body " dangerouslySetInnerHTML={{__html: markdownToHTML1(item.choice_text)}}></span> */}
                   <MarkdownToHtml content={item.choice_text} selector={'multiple_' + (this.props.index + 1) + (key + 1)}
diff --git a/public/react/src/modules/courses/exercise/question/single.js b/public/react/src/modules/courses/exercise/question/single.js
index 510c28b48..a879bad74 100644
--- a/public/react/src/modules/courses/exercise/question/single.js
+++ b/public/react/src/modules/courses/exercise/question/single.js
@@ -16,11 +16,13 @@ class single extends Component{
   changeItem=(e)=>{
     let choiceId=e.target.value;
     let question_id=this.props.questionType.question_id;
+    let {index}=this.props;
     let url=`/exercise_questions/${question_id}/exercise_answers.json`;
     axios.post((url),{
       exercise_choice_id:choiceId
     }).then((result)=>{
       if(result){
+        this.props.changeOption && this.props.changeOption(index,[choiceId]);
         this.props.changeQuestionStatus && this.props.changeQuestionStatus(parseInt(this.props.questionType.q_position)-1,1);
       }
     }).catch((error)=>{
@@ -38,12 +40,12 @@ class single extends Component{
     let isJudge = questionType.question_type == 2
     return(
       <div className="pl30 pr30 singleDisplay">
-        <Radio.Group disabled={ user_exercise_status == 1 ? true : false } defaultValue={questionType.user_answer[0]} onChange={this.changeItem}>
+        <Radio.Group disabled={ user_exercise_status == 1 ? true : false } value={questionType.user_answer[0]} onChange={this.changeItem}>
           {
             questionType.question_choices && questionType.question_choices.map((item,key)=>{
               let prefix = isJudge ?  undefined : `${tagArray[key]}.`
               return(
-                <p className={parseInt(questionType.question_type) == 0 ? "clearfix mb15 df" : "fl mr40"}>
+                <p className={parseInt(questionType.question_type) == 0 ? "clearfix mb15 df" : "fl mr40 df"}>
                   <Radio className="fl lineh-20" value={item.choice_id}>{prefix}</Radio>
                   {/* <span className="fl lineh-20 mr3 "></span> */}
                   {/* <span style={{display:"inline-block", 'margin-top': '-1px'}} className="markdown-body fl " dangerouslySetInnerHTML={{__html: markdownToHTML1(item.choice_text)}}></span> */}
diff --git a/public/react/src/modules/courses/shixunHomework/Listofworksstudentone.js b/public/react/src/modules/courses/shixunHomework/Listofworksstudentone.js
index 6b756ad8f..8ba9b8ac2 100644
--- a/public/react/src/modules/courses/shixunHomework/Listofworksstudentone.js
+++ b/public/react/src/modules/courses/shixunHomework/Listofworksstudentone.js
@@ -367,9 +367,9 @@ class Listofworksstudentone extends Component {
 					render: (text, record) => (
 						<span>
                         {
-													record.submitstate === "未提交" ?<span style={{	color: '#9A9A9A',cursor:"default"}}>--</span>
+													record.submitstate === "未提交" ?<span style={{	color: '#9A9A9A'}}>--</span>
 														:
-														<span style={{textAlign: "center",cursor:"default"}}
+														<span style={{textAlign: "center"}}
 																	className="color-blue"
 																	onClick={() => this.Viewstudenttraininginformation(record)}>{record.operating}</span>
 												}
@@ -691,9 +691,9 @@ class Listofworksstudentone extends Component {
 					align: 'center',
 					className:'font-14',
 					render: (text, record) => (
-						record.submitstate === "未提交" ? <span style={{	color: '#9A9A9A',cursor:"default"}}>--</span> :
+						record.submitstate === "未提交" ? <span style={{	color: '#9A9A9A'}}>--</span> :
 							<span>
-                       <a style={{textAlign: "center",cursor:"default"}} className="color-blue"
+                       <a style={{textAlign: "center"}} className="color-blue"
 													onClick={() => this.Viewstudenttraininginformationt(record)}>{record.operating}</a>
         </span>
 					)
@@ -985,9 +985,9 @@ class Listofworksstudentone extends Component {
 					align: 'center',
 					className:'font-14',
 					render: (text, record) => (
-						record.submitstate === "未提交" ? <span style={{	color: '#9A9A9A',cursor:"default"}}>--</span> :
+						record.submitstate === "未提交" ? <span style={{	color: '#9A9A9A'}}>--</span> :
 							<span>
-                       <a style={{textAlign: "center",cursor:"default"}} className="color-blue"
+                       <a style={{textAlign: "center"}} className="color-blue"
 													onClick={() => this.Viewstudenttraininginformationt(record)}>{record.operating}</a>
         </span>
 					)