使用回转式起重机装卸货时,若船舶横倾接近5度或风大时,应:() ["避免在最小幅度处旋转","快速旋转","避免在最大幅度处旋转","待横倾矫正后再作业"]
钻井液密度过低容易发生()、缩径、卡钻等事故。 ["A、井喷、井塌","B、井喷、井漏","C、井塌、井漏","D、井漏、沉砂卡钻"]
放置克令吊吊臂前,应先将吊臂转到支架上方,再把旋转手柄放在:() ["旋转位置","刹车位置","“零位”空挡位置","松开位置"]
当脚踏转换开关将克令吊吊臂落到支架上后,应再将旋转手柄放回到:() ["旋转位置","“零位”空挡位置","刹车位置","松开位置"]
海市蜃楼是由光的()造成的 ["A、反射","B、折射","C、全反射","D、散射"]
什么事软开关?什么事硬开关