----:     I get up at five o'clock tomorrow morning?

----:  No, you     .

A．Must; can't

B．Must; needn't

C．Can't; can

D．Must; shouldn't

自然界中的生物通过生存斗争，适者生存，不适者被淘汰的过程，称为（　　）

A．人工选择

B．自然选择

C．遗传变异

D．生存竞争