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

<source id="quuqd"><output id="quuqd"></output></source>

<dd id="quuqd"></dd>

<pre id="quuqd"><acronym id="quuqd"></acronym></pre>

單項選擇題

Black smoke coming from a boiler can be caused by （）.

A.low water level
B.high water level
C.excessively high fuel pressure
D.low oil temperature

你可能感興趣的試題

單項選擇題

If a bilge pump failed to build up discharge pressure, you should check for （）.

A.excessive water in the bilges
B.a clogged suction strainer
C.oil in the bilges
D.All of the above

單項選擇題

The shaft and spare parts（） should be well greased in order to avoid corrosion.

A.in the store room
B.in the cylinder
C.in the scavenge air box
D.in the water box

<ins id="lwefj"><tt id="lwefj"><b id="lwefj"></b></tt></ins>