单项选择题 The most crucial time for any bearing with regards to lubrication is （）

单项选择题 If a main propulsion diesel engine hunts excessively at idle speed, you should （）

单项选择题 The amount of fuel delivered for each cycle must be in accordance with the engine load, and the same quantity of fuel must be delivered to each cylinder for each power stroke at that load.Which of the following statements describes this requirement?（）