单项选择题
Which of the following can be directly obtained by means of an indicator card?（）
A.power B.maximum pressure in a cylinder C.mean pressure in a cylinder D.all of the above
单项选择题 Which factor of the following affects not only the fuels combustion but also the engine’s maintenance?（）
单项选择题 Which cause of the following can lead to the engine not to start on air?（）
单项选择题 When turning the engine with turning gear, you should keep the indicator cocks （）.
