【题目】I was taught to sit quietly in class and not to speak______ someone asked me a question.
A.WhenB.unlessC.becauseD.if
在线课程【答案】B
【解析】
考查连词。句意：我被教导要静静地坐在课堂上不说话除非有人问我问题。A. when当……时候；B. unless除非；C. because因为；D. if如果。根据句意，除非有人问我问题，在课堂我就安静地坐着不说话。用unless引导条件状语从句。故选B。