问题补充:
He busy yesterday, or he you 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:考查时态和虚拟语气:句意:昨天他很忙,否则,他就可以帮助你做实验了。第一空是过去的事实,用一般过去式,这里or相当于if he hadn’t been busy这样的虚拟语气条件句,所以后面的主句用would have helped。选B。