For example, a steam engine can use coal, newspaper or wood for the fuel, while an internal combustion engine needs pure, high-quality liquid or gaseousfuel.
例如，蒸汽发动机可以用煤，报纸或木头作为燃料，而内燃机需要用纯的，高质量液体燃料或气体燃料。
2
Messier 27 (M27) is an excellent example of a gaseous emission nebula created as a sun-like star runs out of nuclear fuel in its core.
Messier 27 (M27)是个气体发射星云的典型例子，它是由于类似太阳的恒星耗尽了其核心的核燃料而产生的。
3
Overheating fuel rods then discharge gaseous forms of certain volatile radioactive elements, including cesium, iodine, strontium and tellurium.