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

<progress id="wnyan"><menu id="wnyan"></menu></progress>

<pre id="wnyan"><strong id="wnyan"></strong></pre>

單項選擇題

The internal part of boiler should be welded by yard if found （）.

A.sealed
B.cracked
C.shape changed
D.deformed

你可能感興趣的試題

單項選擇題

The internal part of the boiler, if found （）, has to be chemically washed by yard.

A.deformed
B.rusted
C.cracked
D.scaled

單項選擇題

Centrifugal pumps can be designed with a number of impellers （） to attain a high final delivery pressure.

A.in series
B.in parallel
C.either A or B
D.None of the above is tree