真空脱气法在油田污水除CO2中，还能除去（）。
A.O2
B.N2
C.H2S
D.以上都不对
参考答案：C
______ trees were cut down. And many birds lost their home.
A. Two thousands B. Thousands of D. Thousand of
男，2岁，发热伴咳嗽，诊断为链球菌性肺炎，用抗生素治疗的疗程应持续至体温正常后
A．2～4天B．5～7天C．8～10天D．11～13天E．14～16天
