99色精品-9色在线-99色在线-99色视频国产欧美日产一区二区三区_亚洲精品亚洲人成在线观看_四虎在线精品永久观看_免费一级a一片久久精

<ruby id="rkmvh"><xmp id="rkmvh"></xmp></ruby>

<em id="rkmvh"></em>

<ruby id="rkmvh"><output id="rkmvh"></output></ruby>

單項選擇題

High-speed rotation in a centrifugal purifier can produce a force （） the force of gravity.

A.many thousand times larger than
B.the same as
C.many thousand times smaller
D.none of the above

你可能感興趣的試題

單項選擇題

The separation of impurities and water from （） is essential for good combustion of diesel engines.

A.lube oil
B.fuel oil
C.turbine oil
D.grease

單項選擇題

Which of the following may hardness of the boiler water cause?（）
(1) scale formation
(2) tube failure
(3) corrosion

A.（1）and（2）
B.（1）and（3）
C.（2）and（3）
D.（1），（2）and（3）

<sup id="2x0fr"><small id="2x0fr"><div id="2x0fr"></div></small></sup>