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
本句考查动词的被动语态和时态，it+is+动词ed形式，to do是固定的搭配用法。而Bunsen Burner的发明是过去发生的动作，所以用完成时态。