卷扬机滚筒上的钢丝绳全部放出后,至少要保留3-5圈。()
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多工位装配机通常用于具有()零部件的产品装配。
A. 一个
B. 二个
C. 三个
D. 三个以上
()是指轧件与轧辊接触面的水平投影,它取决于带钢和轧辊直径。
Prior to burning or welding on a fuel tank on a ship,regulations require that an inspection be made. An entry in the unofficial logbook is required if this inspection is made by().
A. a marine chemist
B. the Officer in Charge,Marine Inspection
C. the Master or person in charge of the ship
D. the National Fire Protection Associatio