属于第二类污染物的是（）
A.总汞
B.石油类
C.总铬
D.苯并芘
参考答案：B
— How are the team playing?
— They're playing well, but one of them________hurt. [ ]
A. got
B. had
C. turned
D. become
在片剂的压片过程中要求（）分钟定一量
A、15
B、20
C、25
D、30
