单项选择题 The cooling water jacket is common to all the cylinders but there are often （） to ensure that each cylinder receives the right amount and flow of water.

单项选择题 The cooling water is in direct contact with the outer surface of the liner as a result of which it is termed a （）.

单项选择题 The cooling of the piston is carried out by circulating （） across the underside of the crown and inside the ring belt or through specially shaped passages.