---Mum, could you buy me a dress like this?

---Certainly, we can buy ______ one than this, but ______ this.

A．a better; better than

B．a worse; as good as

C．a cheaper; as good as

D．a more important; good as

含硫污水应密闭送入（）进行处理，禁止排入其它污水系统或就地排放。