HIV感染的高危人群有（）
A.同性恋
B.血友病
C.静脉药瘾者
D.输血一次后
E.HIV感染的母亲所生的婴儿
参考答案：A, B, C, E
—You have to believe in yourself.No one else will，if you don't.
—________.Confidence is really important.
(2012·天津)
A．It's not my cup of tea
B．That's not the point
C．I don't think so
D．I couldn't agree more
对于原子，下列说法正确的是[ ]
A．质子数是20
B．中子数比质子数多了1
C．中子数是19
D．质量数是58
原子，下列说法正确的是[ ]