after that是什么时态的标志

　　The funny thing is it never happened again after that.

　　奇怪的是从那以后这事再也没有发生过。

　　She was in the hospital for a week and laid up for a month after that.

　　她住院一星期后又卧床一个月。

　　After that, food shipments to the port could begin in a matter of weeks.

　　之后，到该港口的食物运送可能在几周之内开始。