__we could not have finished the work on time.A should they not o_英语解答

__we could not have finished the work on time.
A should they not offer to help usB but for their help

想知道A错误在哪里,如何改.答案是B.

人气：425 ℃　时间：2019-10-29 06:32:15

解答

从句子的后半段可以推断,本题考查的是对过去虚拟.
A是对将来虚拟的形式.对过去虚拟的从句结构应当是
if ther had not offered to help us
或 had they not offered to help us
所以不选A
供参考.