单项选择题 The temperature difference between the inlet and outlet temperature of the lube oil cooler in the lubricating system for the diesel engine is generally between （）.

单项选择题 The opening or closing of the cylinder starting valve is controlled by （）.

单项选择题 Suppose the rated capacity of the main engine of a ship is 10,000 KW at 100 rated rpm, then when at 80 rpm its capacity should be （）.