问题补充:
He busy yesterday,or heyou with your experiment.
A. was;had helped
B. was;would have helped
C. had been;would have helped
D. were;would have helped
答案:
A. was;had helped
(答案→)B. was;would have helped
C. had been;would have helped
D. were;would have helped
解析:该题根据交际情景考查时态的用法。第一句有明确的时间状语yesterday,故用过去时。后一句表示过去的动作并没有发生,故用“would have done”。