Unless ____ to speak,  you should remain silent at the conference.A invited     

题型：不详难度：来源：

Unless ____ to speak,  you should remain silent at the conference.
A invited        B inviting          C being invited   D having invited

答案

A

解析

本题考查动词的-ed形式。You 与invite 之间构成被动关系，故用过去分词。Unless invited to speak =" Unless" you are invited to speak. 答案为A。