—Will you give me a hand? I have some trouble_______ the scientific problem.

—Don't worry. I'll try my best to help you _______.

A．solving; in five minutes

B．to solve; in five-minute

C．to solve; after five minutes

D．solving; after five-minutes

仓储的作用不包括（）。

A.时间效用

B.蓄水池作用

C.保存商品的使用价值

D.空间效用