确定一个人是否感染了艾滋病病毒主要依靠（）
A.临床表现
B.血液中艾滋病病毒抗体或抗原检测
C.是否有高危行为
D.不知道
参考答案：B
If you were being assisted by an icebreaker and he sent you the single letter Q，he would be telling you（）.
A.that he has his engines in reverse
B.that he is shortening the distance between vessels
C.to shorten the distance between vessels
D.that his vessel is healthy
寒潮天气的主要天气特征为（）
A.偏北大风
B.持续低温
C.A、B都对
D.A、B都错
