— Do you think yesterday’s math problem was difficult?

— Yes. I could           work it out.

A．hardly

B．easily

C．finally

D．nearly

在钻遇某岩层时，钻井液的密度、黏度、失水量、切力、含盐量都剧增，则该岩层是（）。

A、盐层

B、石膏层

C、疏松砂岩层

D、黏土层