97免费在线观看视频,亚洲综合自拍网,黄色毛片免费观看,热久久综合网,免费看日产一区二区三区狠狠操av,久久久涩涩涩,在线精品免费视频,人人插天天干,久久91精品国产91久久

<nav id="r2u2i"></nav>

<xmp id="r2u2i"><thead id="r2u2i"><b id="r2u2i"></b></thead></xmp>

<acronym id="r2u2i"><del id="r2u2i"></del></acronym>

單項(xiàng)選擇題

The refrigerant leaves the evaporator of a refrigeration system as a low pressure （）.

A.sub-cooled liquid
B.high temperature liquid
C.oil saturated liquid
D.superheated vapor

你可能感興趣的試題

單項(xiàng)選擇題

When operating with a negative suction head, which of the following types of pumps will require priming?（）

A.Reciprocating
B.Centrifugal
C.Rotary
D.Gear

單項(xiàng)選擇題

The discharge rate or capacity of a centrifugal pump will vary directly as the （）.

A.change in the impeller diameter
B.square of the impeller radius
C.cube of the impeller diameter
D.impeller efficiency for large changes in its size