—Mum, may I watch TV now?

—No, you ______ finish your homework first. [ ]

A. mustn't

B. must

C. need

D. can't

老鼠对人类有害并被列为“四害”之一，我们对它应 [ ]

A．想尽办法赶尽杀绝　　　

B．顺其自然不加控制

C．大力保护并减少其天敌的数量

D．设法控制其数量，减少危害