徒手攀登消防梯时,操作规程()。
A.双手不得同时离梯
B.保护人员可有可无
C.梯子未锁牢挂稳前,严禁攀登
D.二楼以上登高时,必须使用安全绳保护
参考答案:A, C, D
________in the queue for half an hour, the old man suddenly realized he had left the cheque in the car.
[ ]
A. Waiting
B. To wait
C. Having waited
D. To have waited
电容器的电容量 ,极距变化型的电容传感器其灵敏度表达式为:()。