普通干粉灭火剂能用于扑灭()火灾。
A.A类
B.B类
C.C类
D.D类
E.E类
参考答案:B, C, E
Tom is very modest. He never ___________ before his friends.
A.shows off
B.shows up
C.turns off
D.turns on
水泥沙浆是用()混合成的。