1、19.Charles Babbage is generally considered ______ the first computers.

问题描述:

1、19.Charles Babbage is generally considered ______ the first computers.
A.to invent
B.inventing
C.to have invented
D.having invented
请问这题为什么选C而不选A呢

be considered to do sth 被认为去做某事,这件事是还没做的,不定式to do有将来的含义
而be considered to have done 被认为做过某事,to have done是不定式的完成式,表示这事情已经做过了,发生在过去