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

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：结合语境这里描述当时的情况，宜用一般过去时。