Question

Why didn't you remind him of the possible danger?

But what ____ otherwise? He never listens to me．
A．could I do B．could I have done C．should I do D．must I have done

Answer 1

otherwise，此句使用虚拟语气。
对现戚圆仿在的虚拟：would + do；
对过高纤去的虚拟腔镇：would + have done。

--Why did you leave without a word of warning to John?
为什么你不教训一下约翰就走了？
--But what could I have done otherwise? He never likes to listen to me.
不然我还能做什么呢？他从来都不听我的。

Answer 2

A