He knew nothing about the plan _____he came into the room.A.when B.until C.since D.so

题目

He knew nothing about the plan _____he came into the room.A.when B.until C.since D.so
我们的月考题,总觉得A和B都对,到底选什么呢?老师说是B,那A为什么不对呢?

答案

B not ... until句型nothing相当于not