单项选择题
You should （松）（）the mooring lines at the same time when the wind is big.
A.fasten B.slack C.fast D.slacken
单项选择题 When we meet a（军舰）（）, we should lower national flag.
单项选择题 PSC officers will come on board for(检查)（）next Monday.
单项选择题 They will take measures against (海盗)（）and pilferage.
