--- Can I join their club?

--- I am afraid you will be refused __________ you’ve passed all their tests.

A．if

B．when

C．unless

D．since

在保证电网和水电厂安全运行的前提下，依据设计文件及用水计划，尽力满足（）的需要，统筹兼顾、多方共赢。

A.发电效益

B.综合用水

C.防汛安全

D.电网稳定