ke兼容问题：

db/migrate/20190805010562_modify_ke_contents_for_markdown.rb

@@ -5,8 +5,8 @@ class ModifyKeContentsForMarkdown < ActiveRecord::Migration[5.2]
       return content if content.blank?
       s_contents = sanitize(content, tags: %w(img a table td tr tbody pre), attributes: %w(src href target style))
       s_contents.gsub(">\n<", "><").gsub(/^\n/, "").gsub(" ", "").gsub(/(\n)+/, "<br />")
-          .gsub("\t", "").gsub("    ", "&nbsp;&nbsp;&nbsp;&nbsp;").gsub("\n", "<br />")
-          .gsub(/(<br\s?\/?>)+/, "<br />")
+          .gsub("\t", "").gsub("\n", "").gsub("    ", "&nbsp;&nbsp;&nbsp;&nbsp;").gsub(/(<br\s?\/?>)+/, "<br />")
+      s_contents.gsub("\n", "<br />").gsub(/(<br\s?\/?>)+/, "<br />")
     end
     #
     # # 课程讨论区
@@ -16,7 +16,7 @@ class ModifyKeContentsForMarkdown < ActiveRecord::Migration[5.2]
     # end
 
     #试卷的标题
-    ExerciseQuestion.where(:exercise_id => 1890).find_each do |eq|
+    ExerciseQuestion.where(:exercise_id => 1892).find_each do |eq|
       puts("#eq.question_title: #{eq.question_title}")
       question_title = ke_transform_to_md eq.question_title
       puts("#question_title: #{question_title}")