我国的《公路沥青路面再生技术规范》建议水泥等活性填料一般不超过（）
A.1%
B.1.5%
C.2%
D.2.5%
参考答案：B
—Who is making so much noise in the garden?
—______ the children.
A．It is
B．They are
C．That is
D．There are
试述氯丁橡胶的生产。
