幻灯片在放映过程中终止放映的按（）键。 Ctrl。 Alt。 Del。 ESC。
Excessive air leakage into the suction side of a centrifugal pump would be indicated by which of the following operational problems?（） The pump delivers full capacity when started, but gradually slackens off toan abnormally low flow。 The pump packing gland overheats after short operating periods。 The motor over-current protective device continually shuts the pump down。 Pounding noises can be heard at the pump suction chest。
人体触电时的危险性与哪些因素有关？
集装箱的重量分为（）。 自重。 载重。 额定自重。 额定重量。
The wooden plug inserted in the vent of a damaged tank should be removed if you are going to （）. pump from the damaged tank。 fight a fire。 abandon ship。 use the crossover system。
我国法律关系客体主要包括（）
