问题详情：
![Itissaidthatpotatochips]( "Itissaidthatpotatochips")
It is said that potato chips ______by mistake about a hundred years ago.
A. invent B. invented
C. are invented D. were invented
【回答】
D 句意：据说薯片是大约一百年前偶然被发明的。本题考查动词的时态和语态。由时间状语a hundred years ago可看出句子应用一般过去时；potato chips与invent构成被动关系，故选D项。
知识点：动词语态
题型：选择题
