Brushless generators are designed to operate without the use of（）. ["brushes","slip rings","commutators","all of the above"]
The reference datum used in determining the heights of land features on most charts is（）. ["mean sea level","mean high water","mean low water","half-tide level"]
从交际功能的角度来看，（）是全身接受非语言交际行为最重要的组成部分。 ["目光","上肢","下肢","肢体动作"]
检务档案保管期限：一般出境检验检疫档案为（）；入境检验检疫档案为（） ["三年；四年","二年；三年","四年；三年","三年；二年"]
顾问式销售与普通销售的主要区别（）。 ["顾问式销售员对产品的性能有更清楚地了解","顾问式销售员更能减少客户的抱怨","顾问式销售员能了解客户抱怨背后真正的原因是什么以及解决的方法","顾问式销售员有很好的感染力"]
何谓提单？
