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

單項選擇題

All three systems have the ports （） to swirl the incoming air and direct it in the appropriate path.

A.angled
B.rounded
C.being angled
D.being rounded

你可能感興趣的試題

單項選擇題

All the rings are slightly rounded on their external top and bottom edges to keep the oil film on the cylinder liner during （） for new piston rings.

A.the running-in period
B.the running process
C.gas exchange process
D.the boiler firing

單項選擇題

Air cocks, usually positioned at the （） in a circulating system, is used to get rid of the air in the system.

A.bending joint
B.expansion tank
C.weld
D.the highest point

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