问题补充:
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
答案:
A. to be invented
B. having been invented
C. invented
(答案→)D. to have been invented
解析: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。