单项选择题
The sailor taking （）watch should do cleaning work on the bridge.
A. 0 to 4 B. 4 to 8 C. 8 to 12 D. 12 to 16
单项选择题 The sailors do cleaning and repair work under the supervision of the （）.
单项选择题 Cleaning is a constant job （）board a ship.
单项选择题 Cleaning is a frequent （）on board a ship.
