对吸入的气体有温暖、湿润、清洁作用的结构是[ ]
A．口腔
B．咽
C．鼻
D．喉
答案：C
一元二次方程（2x-1）2-7=x化为一般形式______．
--Must we move to the next room?
--No, you____________ . You may still live here if you like.
A．mustn't
B．don't
C．don't have to
D．won't
