启动计量泵时，应打开（）。
A.返回阀
B.进口阀
C.出口阀
D.储罐放空阀
参考答案：A
The Bird Nest _____ in Beijing the year before last. It was for the 2008 Olympic Games. [ ]
A. build
B. was built
C. was building
D. built
尿比密升高见于（）。
A.婴幼儿
B.尿崩症
C.慢性肾小球肾炎
D.心功能不全
E.肾盂肾炎
