Most people take clean water for granted, but we ________ any if we don't stop polluting the rivers and

lakes.[ ]

A．don't have  

B．won't have

C．haven't had  

D．didn't have

董事会对经理实行监控的主要手段是()。

A.期权控制

B.契约控制

C.外部控制

D.对经理的任免及报酬决定权