PC端答题优化

@@ -517,6 +517,7 @@ class Exam extends Api
                 if(!empty($correct)){
                 if(!empty($correct)){
                     $correct = explode(',',$correct);
                     $correct = explode(',',$correct);
                 }
                 }
+                $answer1 = [];
                 if(!empty($answer)){
                 if(!empty($answer)){
                     $answer1 = explode(',',$answer);
                     $answer1 = explode(',',$answer);
                 }
                 }