为了保护听力,在一般情况下应该控制噪声不超过( )
A.110dB
B.90dB
C.50dB
D.30dB
答案:B
The worker wasn't on duty that night. He shouldn't _____ the accident. [ ]
A. see to
B. see at
C. see for
D. see from
下列超重工具和起重机械中,( )适用于小型设备和重物的短距离吊装,一般的起重量为0.5~1t,最大可达2t。
A.千斤顶
B.吊钩
C.倒链
D.手拉葫芦