先看一遍，文教授/專家好象說過會給你看的。
A locomotive has to be added fuel, such as coal, firewood, or other flammable substance, consuming which may provide motion or energy for the machine.
可能是我少見多怪，定語從句的連詞前隻用介詞而不用分詞？
為什麽不先原文那樣分為兩句？
The body of an animal also needs fuel supplementation being called food, which may provide energy to the animal.
may is not needed?
In order to ignite the flammable substance and oxidize the food in the animal body, oxygen is essential.
ignite --> burn or combust.
The locomotive is composed of special parts: the hearth to accept and ignite the flammable substance, the pipe to transport steam, the wheel to make the locomotive move on, and the chimney to exhaust gas.
hearth ?
gas --> waste gas
While the animal body is also composed of different parts: gastrointestinal tract to ingest and absorb food, the emunctory organ to evacuate waste, the arteries and veins to transport oxygen and store nutriment, and the legs and wings to move on.
the legs and wings to move on 沒有翻出原意：使動物行進的腿或翅膀
