单项选择题 However fast or slow the combustion rate, it is still a （） between carbon, hydrogen, sulphur and oxygen that releases heat.

单项选择题 The trend nowadays is to build the frame box as a separate fabricated construction and then, after stress relieving and machining the mating surfaces, to mount it on the （）.This has the advantage of saving weight.

单项选择题 If the bedplate was too rigid, then as the hull flexed, the （）, which secure the engine into the ship would be likely to break, and there would be a danger of the bedplate cracking.