l have taught English in the middle school ___1980

问题描述:

l have taught English in the middle school ___1980
A for
B since
C in
D after 选哪个,为什么?

l have taught English in the middle school since 1980
这个句子是现在完成时,用in ,after的话前面就应该是 i taught.
如果用for的话,后面就应该接一段时间,例如3 years,很显然1980不是一段时间.