They considered a computer,which was considered a great help in their work.这里该选哪个

问题描述:

They considered a computer,which was considered a great help in their work.这里该选哪个
A.to buy; to be B.buying; being C.to buy; being D.buying; to be

D
consider后面一般加动词ing形式
consider sth (to be)+名词、形容词……
变为被动就成了sth be considered (to be)+名词、形容词……