They considered a computer which was considered a great help in their work.A. to buy;

问题补充：

They considered a computer, which was considered a great help in their work.

A. to buy; to be

B. buying; being

C. to buy; being

D. buying; to be

答案：

A. to buy; to be

B. buying; being

C. to buy; being

(答案→)D. buying; to be

解析：考查动词consider 的用法:考虑做某事 consider doing, 被认为 be considered to be ,根据题意应选D 。