Question

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

1. A.
   to be invented
2. B.
   having been invented
3. C.
   invented
4. D.
   to have been invented

Answer 1

D
本句考查動(dòng)詞的被動(dòng)語態(tài)和時(shí)態(tài)，it+is+動(dòng)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(dòng)作，所以用完成時(shí)態(tài)。