单项选择题
You should slack the mooring lines （）when the wind is big.
A. at the same time B. on time C. in time D. at times
单项选择题 We must （）to inspect the problems about the safety of fire prevention.
单项选择题 When you keep a gangway watch, you should （）the mooring lines according to the rise and fall of the tide.
单项选择题 Lower gangway into place and （）safety net.
