Today the forests are getting ____________, we must ________ down  too many trees.

A．more and more, prevent people cutting

B．fewer and fewer, stop people cutting

C．smaller and smaller, keep people cutting

D．bigger and bigger, keep people from cutting

防水混凝土的（）必须符合设计要求。

A.抗压强度

B.抗折强度

C.抗裂强度

D.抗渗压力