The Bunsen Burner is so named because it is thought by Robert Bunsen.A. to be inventedB.

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。