1.He has been in the army for three years?_____ _____three years since he _____the army.

问题描述:

1.He has been in the army for three years?_____ _____three years since he _____the army.

_Have____ _yet____three years since he _in____the army?

It is, joined
前面三格的话:It has been(等同的)

it has been ;joined
since 引导的句子 主句用现在完成时 ;他是过去参军的,而且参军是非延续动词 所以用过去时 joined