i have been a teacher for twenty years.i ___ a teacher twenty years ___ (保持句意不变)

问题描述:

i have been a teacher for twenty years.
i ___ a teacher twenty years ___ (保持句意不变)

was ago
20年前,我就是一名教师。

第一个空wasn't
第二个空ago

I became a teacher twenty years ago.

i became a teacher twenty years ago.

I have been a teacher for twenty years.
我已经做了20年教师了.
I _became__ a teacher twenty years __ago_ .