Fix typos in 'Async jobs' (#1418)

tutorials/katacoda/case-async-jobs-cn/switch-foregd-backgd.md

@@ -1,6 +1,6 @@
 
-* When a job is executed in the background or in suspended status (use `ctrl + z` to suspend job), `fg <job-id>` can transfer the job to the foreground to continue to run.
+* 任务在后台执行或者暂停状态（`ctrl + z`暂停任务）时，执行`fg <job-id>`将可以把对应的任务转到前台继续执行。在前台执行时，无法在console中执行其他命令
 
-* When a job is in suspended status (use `ctrl + z` to suspend job), `bg <job-id>` can put the job to the background to continue to run.
+* 当任务处于暂停状态时（`ctrl + z`暂停任务），执行`bg <job-id>`将可以把对应的任务在后台继续执行
 
-* A job created by other session can only be put to the foreground to run by using `fg` in the current session.
+* 非当前session创建的job，只能由当前session `fg`到前台执行

tutorials/katacoda/case-async-jobs-en/switch-foregd-backgd.md

@@ -1,6 +1,6 @@
 
-* 任务在后台执行或者暂停状态（`ctrl + z`暂停任务）时，执行`fg <job-id>`将可以把对应的任务转到前台继续执行。在前台执行时，无法在console中执行其他命令
+* When a job is executed in the background or in suspended status (use `ctrl + z` to suspend job), `fg <job-id>` can transfer the job to the foreground to continue to run.
 
-* 当任务处于暂停状态时（`ctrl + z`暂停任务），执行`bg <job-id>`将可以把对应的任务在后台继续执行
+* When a job is in suspended status (use `ctrl + z` to suspend job), `bg <job-id>` can put the job to the background to continue to run.
 
-* 非当前session创建的job，只能由当前session `fg`到前台执行
+* A job created by other session can only be put to the foreground to run by using `fg` in the current session.