单项选择题
There are many kinds of （）(舱盖) on board a ship.
A.hatch covers B.hatches C.holds D.bulkheads
单项选择题 （）(国旗) should be put on the stern of the ship.
单项选择题 Deck officers work on the （）(驾驶台甲板).
单项选择题 There are some （）(螺帽) in the toolbox.
