阀控式密封铅酸电池的节流阀是用来：（）
A.排水
B.排气体
C.加水
D.检测
参考答案：B
Jobs are hard to get and, ________， more young people are continuing their education.[ ]
A. above all
B. as a result
C. after all
D. on the contrary
Rh血型系统最早是由下列谁发现
A．Landsteiner和WienerB．LevineC．StetsonD．LandsteinerE．Wiener
