问题补充:
We would have called a taxi yesterday if Harold us a ride home.
A. didn offer
B. wouldn offer
C. hasn offered
D. hadn offered
答案:
A. didn offer
B. wouldn offer
C. hasn offered
(答案→)D. hadn offered
解析:考查虚拟语气。本题是条件状语从句的虚拟语气,从句中用过去完成时表示与过去事实相反,主句用情态动词+have done.故D正确。