单项选择题
If the engine does start on air, but combustion does not immediately begin, the cause may not be （）.
A.low compression B.failure of the fuel pump to discharge fuel C.incorrect timing of fuel pump D.turning gear being still on
单项选择题 If the engine does start on air, but combustion does not immediately begin, the cause may be （）.
单项选择题 If the engine does not start on air, it may be due to （）
单项选择题 If the engine （） for a long period, there will be a danger of frost.
