单项选择题
A. Sailors often maintain the derrick. B. Sailors often maintain the winch. C. Sailors often maintain the windlass. D.Sailors often maintain the machine.
A. I usually keep watch on the bridge. B. I often do some repair work on the forecastle. C. I often paint on deck. D. I often do some repair work on the bridge.
A. Put rat guard on the deck. B. Put rat guards on the moorings. C. Put rat guard under the moorings. D. Put rat guards under the moorings.