隧道施工过程中的防尘措施有()。
A.湿式凿岩
B.机械通风
C.喷雾洒水
D.佩戴防护口罩
参考答案:A, B, C, D
E-mail , as well as cellphones, _____an important part in daily communication.
A.have played
B.play
C.are playing
D.is playing
用NaOH标准溶液滴定HAc的过程中,化学计量点偏碱,应选用()为指示剂
A.甲基橙
B.酚酞
C.溴酚蓝
D.甲基红