信号电源电压不得大于（）V，提升装置的直接供电线路上严禁分接其他负荷。
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Finally，when your ship is alongside，don’t forget（）.
A. having rat guards properly mounted on your moorings
B. to have rat guards properly mounted on your moorings
C. to have rat guards properly mounting at your moorings
D. having rat guards proper mounted on your mooring
切削铸铁等脆性材料时，一般（）。
A. 不加切削液
B. 选用相应切削液
C. 选用乳化液
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