-- Are you sure that he will come here in time?

--- You may ______ he will come to help us though he is very busy.

A．rely upon that

B．rely upon it that

C．rely upon what

D．rely upon it what

根据引起爆炸的原因和过程不同，可将爆炸分为（）。

A．物理爆炸

B．化学爆炸

C．核爆炸

D．聚变

E．裂变