The most serious problem we are facing now is how to ______ all the pollution.

A．get rid of

B．get on with

C．get through with

D．get down to

概算指标的作用主要有( )的主要依据。

A．作为编制投资估算

B．估算主要材料用量

C．建设单位选址

D．确定投资额

E．工程结束后，进行竣工决算和评价