单项选择题
Routine maintenance of lead acid batteries should include （）.
A.keeping the terminals clean B.coating cable connections with petroleum jelly C.maintaining a trickle charge D.All of the above
单项选择题 Under which of the listed conditions can the engine room retake the throttle control from the bridge（）.
单项选择题 Copper is often used as an electrical conductor because it （）.
单项选择题 A device which prints out a permanent record of the plant operating conditions is known as the （）.
