The diameter of the gravity disc is too big It causes oil to flow through the water outlet We changed the disc and no （） is found in the water outlet.

[单选题]In a purifier changing to a gravity disc with larger hole diameter will move the interface towards the （）.A . bowl peripheryB . bowl centerC . upper surfaceD . lower surface

[名词解释] Embryonic disc

[名词解释] 视盘（optic disc）

[单选题]F．or a purifier changing to a gravity disc with smaller hole diameter will move the interface towards the _______.A．bowl peripheryB．bowl centerC．upper surfaceD．lower surface

[单选题]It can be interred that without gravity .A．buildings and other structures would float awayB．trees and buildings would not so easily fly offC．something around your head would not float awayD．everything outside buildings would fly off into space

[单选题]If the vertical center of gravity (VCG) of a ship rises 1.7 feet，the righting arm (GZ) for the various angles of inclination will（）.A . decreaseB . increaseC . remain unchangedD . be changed by the amount of GG' x cosine of the angle

[名词解释] 重力坝（gravity dam）

[名词解释] 尿比重（urinaryspecific gravity，SG）

[单选题]A crankshaft whose center of gravity coincides with its center line is said to be （）.A . dynamically balancedB . statically balancedC . counter balancedD . resonantly balanced

[单选题]The outside diameter of the pipe is （） the diameter of the bore of the piston rod, the result being that an annular space formed between the piston rod and the pipe.A . less thanB . greater thanC . equal toD . twice larger tha