单项选择题 The best tool to use for removing the carbon ridge at the top of an enginecylinder, prior to removing the piston, is to use（）

单项选择题 Which of the following problems can cause an above normal air temperature to develop in the intake manifold of a turbocharged and after-cooled diesel engine?（）

单项选择题 Which of the following conditions can cause below normal air pressure in the intake manifold of a turbocharged diesel engine?（）