同步电动机最主要的特点是：负载在一定的范围内变化时，电动机的转速不变。
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（）是指用水作为洗涤溶剂，借助肥皂或洗涤剂，在适当的温度条件下进行洗涤的方法。
A. 湿洗
B. 干洗
C. 水洗
D. 手洗
在沿海中小港口间，尚有许多地方性航线，主要为（）转运、集散物资服务，并担负部分客运。
电杆拉线穿越带电线路时，应在拉线上加装绝缘子，拉线绝缘子自然悬垂时距地面应不小于（）
A. 1.5m
B. 2m
C. 2.5m
D. 3m
You are crossing a narrow channel in a 15-meter vessel when you sight a tanker off your port bow coming up the channel. Which statement is TRUE? （）
A. Yours is the give-way vessel because it is less than 30 meters long
B. You shall not impede the safe passage of the tanker
C. The tanker is the stand-on vessel because it is to port of your vessel
D. The tanker is the stand-on vessel because it is the larger of the two vessel
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