If they _______ the contract ahead of time,they could not have mi_英语解答

If they _______ the contract ahead of time,they could not have missed the plan.
A signed
B had signed
C would have signed
D should sign
选哪一个?

人气：339 ℃　时间：2019-11-24 17:42:10

解答

B 虚拟语气,根据后边一句说明这里是过去完成时虚拟语气的考察