—When() you ()the army?In 1978.Since I ()17 years old

问题描述:

—When() you ()the army?In 1978.Since I ()17 years old
A.have...joined;was
B.did...join;was
C.have...joined;have been
D.did join;have been
—When() you ()the army?
— In 1978.Since I ()17 years old

答案:B
整句翻译:你何时参军的?在1978年.自从我17岁就参军了
in 1978 是一般过去时的时间状语
since 从句用一般过去时
不明白的再问哟,请及时采纳,多谢 !