当PEG浓度大于多少时，选择性沉淀循环免疫复合物特性消失()
A．1%
B．2%
C．3%
D．4%
E．5%
参考答案：E
23.—Good morning, New York Hotel.
—Hello, I’d like to book a room for the nights of the 2nd and 3rd.
—__________.
A．No problem
B．Just a minute, please
C．What can I do for you?
D．What’s the matter?
面积相等的三角形，形状一定相同．______．
