after必须用在过去完成时中吗?可以after she wrote the letter she went to the post office.用于过去完成时的词 when .after .as soon as .until .by that time这些词是否可以用在过去式中呢，最好请举个例子，
问题描述：
after必须用在过去完成时中吗?
可以after she wrote the letter she went to the post office.
用于过去完成时的词 when .after .as soon as .until .by that time这些词是否可以用在过去式中呢，最好请举个例子，
答
可以的，表示过去发生事实可以用一般过去时。
答
after必须用在过去完成时中吗?
不一定.但你给的例句也不对.以下的修改同时也回答了第一个问题：
After she finished writing the letter,she then went to the post office.
问题补充的例句：
He went to the US when he was 14 years of age.
After/As soon as he finished dinner,he went back to work.
He did not go to sleep until it was midnight.
By that time,he was only 11,too young to understand.