[单选] Which of the following precautions should always be carried out in dry dock?（）

压缩介质为天然气的往复压缩机容易出现由于（）而引起压缩机排气温度高、压力低。 碳析出。 水析出。 杂质。 凝液析出。 Because most，if not all，of the evidence（）the carrier，the burden of proof soon shifts to the carrier，once the claimant has made initial proof of improper care. are available for。 is available to。 are available to。 is available for。 造成往复压缩机排出温度高，但不会使压缩机过热的是（）。 缸头或水夹套积垢严重。 冷却器积垢严重。 气阀损坏。 缸套、活塞或活塞环过分磨损。 Which of the following statements about pump operations is NOT a correct statement?（） In order for a fluid to be pumped, a fluid must be made to flow。 A substance must be cold in order for it to be pumped。 The kinetic energy imparted by the pump can be used to force a liquid through a hydraulic system。 A pump must receive its energy from an external source。 保护现场的原始状态，包括（）不随意挪动位置。 人员。 痕迹。 车辆。 散落物。 Which of the following precautions should always be carried out in dry dock?（）