Question

The Bunsen Burner is so named because it is thought ___________ by Robert Bunsen.

A. to be invented                   B. having been invented

C. invented                         D. to have been invented

Answer 1

D

解析:

本句考查動詞的被動語態(tài)和時態(tài)，it+is+動詞ed形式，to do是固定的搭配用法。而Bunsen Burner的發(fā)明是過去發(fā)生的動作，所以用完成時態(tài)。