---Must we leave the classroom now?

---No, you _____. You _____ leave after the bell rings.

A．mustn't; are allowed to

B．don't have to; might

C．needn't; can

D．can't; are supposed to

下图为“某年我国贵阳、杭州、北京三个城市日照时数”，完成下列各题。

贵阳、杭州、北京的代码依次是（）

A．①②③

B．②③①

C．③②①

D．②①③