与机体酸碱平衡有密切关系的是（）
A.Na+
B.K+
C.Ca2+
D.Cl-
E.HCO-
参考答案：E
The photographer needs to charge up the digital camera every day as the battery ________ quickly. [ ]
A. shuts up
B. ends up
C. runs out
D. turns out
脱乙烷塔顶回流泵不上量的原因有哪些？
