机动船抛锚掉头的过程中应当()。
A.不属在航
B.属于在航
C.属于锚泊
D.以上都对
参考答案:B
For ages, Bill Gates has been supporting educational programmes that ______from kindergartens to universities.
A.range
B.move
C.vary
D.spread
确定事故的直接原因主要从两个方面来考虑:能量源和()。
A.特殊环境
B.危险物质
C.产品性能
D.装配不良