If an attempt is made to hoist a load that exceeds the capacity of an electric winch,an overload safety device causes a circuit breaker to cut off the current to the winch motor().
A. when the line pull reaches the rated winch capacity
B. after the line pull exceeds the rated winch capacity
C. after a short build-up of torque
D. immediately
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蓄电池放电低于终止电压时,再继续进行放电,可能会造成蓄电池永久性的损坏。
A. 正确
B. 错误
晨检工作应在婴幼儿每天清晨()时进行,寄宿制幼儿园应在婴幼儿早晨起床以后进行。
抗代谢类抗癌药是()抗生素类抗癌药是()激素类抗癌药是()细胞毒类抗癌药是()
A. 环磷酰胺
B. 氟尿嘧啶
C. 放线菌素D
D. 长春新碱
E. 他莫昔芬
我国海水环境严重受冻港水位变动区钢筋混凝土及预应力混凝土的抗冻等级标准为()。
A. F300
B. F350
C. F400
D. F450