It is desirable that water used for drinking（ ）pure.

It is desirable that water used for drinking（ ）pure.


A、

were


B、

should be


C、

is


D、

ought to be


【正确答案】：B
【题目解析】：

本题考查虚拟语气，it is desirable that后面要用虚拟语气，should do，选B。句意：饮用的水应该是纯净的，这是可取的。