期货实物交割方式包括( )。
A．现货交割
B．现金交割
C．滚动交割
D．集中交割
参考答案：C,D
I don’t know________.
Because he has to look after his mother.
A．why he is leaving
B．why is he leaving
C．whether he is leaving
D．whether is he leaving
煤矿防治水工作应当采取“（）、排、截”综合防治措施。
A.探
B.防
C.堵
D.疏
