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

<i id="kv7ot"></i>

<ruby id="kv7ot"><small id="kv7ot"></small></ruby><em id="kv7ot"></em>

<sup id="kv7ot"><legend id="kv7ot"><div id="kv7ot"></div></legend></sup>

單項(xiàng)選擇題

The（）is fitted in the main steam supply line and is usually of the non-return type.

A.main steam stop valve
B.auxiliary steam stop valve
C.feed check or control valve
D.blow down valve

你可能感興趣的試題

單項(xiàng)選擇題

The lifting pressure of （） is set in the presence of a Surveyor it is locked and cannot be changed.

A.fuel valves of main engine
B.injector pump of main engine
C.safety valves of marine boiler
D.safety valves of a reciprocating pump

單項(xiàng)選擇題

The propeller is pushed on to the tubeshaft taper and made tight by（）

A.a mechanical seal
B.keyway and key
C.a nut
D.shrinkage

<ruby id="crtqu"><small id="crtqu"></small></ruby>