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

<pre id="vfyke"><legend id="vfyke"></legend></pre><pre id="vfyke"><strong id="vfyke"></strong></pre>

<sup id="vfyke"><pre id="vfyke"><div id="vfyke"></div></pre></sup>

單項(xiàng)選擇題

The water in an auxiliary boiler should be tested daily for （）.

A.dissolved oxygen
B.chlorides
C.sludge
D.dissolved nitrogen

你可能感興趣的試題

單項(xiàng)選擇題

A feed pump for an auxiliary boiler might lose suction if the （）.

A.boiler water level is low
B.feedwater is too hot
C.boiler steam demand is low
D.feedwater is too cold

單項(xiàng)選擇題

Fuel is admitted to a diesel engine cylinder through the （）.

A.intake valves
B.carburetor
C.exhaust ports
D.injector nozzles

<dd id="jj8k5"></dd>