路面垫层采用粗砂或天然砂砾时，小于0.075mm的颗粒含量应小于( )。
A．10%
B．8%
C．7%
D．5%
参考答案：D
—Are you free this afternoon?
—________ I have to meet my brother in the station (车站). [ ]
A. I think so.
B. Yes, I am.
C. I'm afraid not.
D. Right.
膨胀阀毛细管没有与管路贴合，将会使空调系统（）
A.低压管过冷
B.低压管过热
C.不制冷
