He busy yesterday, or he you with your experiment.
A. was; had helped
B. was, would have helped
C. had been; would have
D. were; would have helped
网友回答
A. was; had helped
(答案→)B. was, would have helped
C. had been; would have
D. were; would have helped
解析：考查时态和虚拟语气；第一空的时间状语是yesterday，故使用一般过去时。因为有含蓄的条件，用or(否则，要不然)，第二空是一个与过去事实相反的虚拟语气，使用“情态动词+have done”的形式；句意：昨天他很忙，要不然，他就会帮助你做实验。故B正确。