—Do you think that man will come to your help?

—I really don’t know       a person like him can help me with.

A．how

B．what

C．why

D．if

处于动态平衡的汽、液共存的状态叫（）。

A.饱和状态；

B.不饱和状态；

C.过热状态；

D.再热状态。