单选题 The teacher didn't begin the class ______ all the students ______．
[A] until, stopped talk [B] before, stopped talking
[C] while, stopped to talk [D] because, stopped talking

【正确答案】 B

【答案解析】[解析] 本题考查动词的用法。Stop doing sth. 的意思是“停止做某事”，而stop to do sth. 的意思是“停下来去做某事”，所以本题应该选stopped talking。此外，根据本句的句意“老师等所有的学生停止讲话才开始上课”，本题应该选until或before。根据这两点，此题答案为[B]。