一般用冷的时间为
A．5～10分钟
B．10～15分钟
C．10～30分钟
D．30～40分钟
E．以上均不是
参考答案：C
79. There are only five minutes left before the train leaves. You should run _______ .
A．fast as possible as you can
B．as quickly as you can
C．as fast as possible
D．possible as fast as you can
掘进机第二运输机保证不漏料可回转（）
A.±16°
B.±18°
C.±30°
D.±45°
