---Why didn’t you go to yesterday’s meeting?---I would have but I too busy working on the

问题补充：

---Why didn’t you go to yesterday’s meeting?

---I would have but I too busy working on the important experiment.

A. had been

B. was

C. were

D. am

答案：

A. had been

(答案→)B. was

C. were

D. am

解析：根据前半句是I would have (gone to…),可知这里要表达的意思是：我本来是去的，但是…当时太忙了,所以确定用一般过去时.