单项选择题
It（）as a shock to realize that I was not alone in the room.
A.came B.appeared C.arrived D.reached
单项选择题 （）so many people in the United States been out of work as today.
单项选择题 When he suddenly（） up the subject of genetic engineering, there was an embarrassed silence.
单项选择题 The problem（）when the students refused to do their homework.
