按“废品落户”的有关规定进行钢质和轧钢操作废品的区别，（）属于钢质废品。
A．气泡
B．麻面
C．耳子
参考答案：A
The naughty boy had wanted to play football with the kids in the street, but his parents warned him ____.
A．not to
B．not to do
C．to do
D．of doing
根据《建筑地基基础设计规范》(GB50007-2002)的规定，柱下钢筋混凝土扩展基础设计时，其混凝土强度等级( )。
A．不应低于C20
B．不应低于C25
C．不应低于C30
D．不应低于垫层混凝土强度等级
