n. a very light colorless element that is one of the six inert gasses; the most difficult gas to liquefy; occurs in economically extractable amounts in certain natural gases (as those found in Texas and Kansas)
n. 氦
[化] 氦
1. Helium is lighter than air, which is why balloons filled with it float.
氦气比空气轻，这就是为什么充满氦气的气球会飘起来。
2. Many people use helium to fill balloons for parties and celebrations.
很多人用氦气为派对和庆祝活动充气球。
3. Helium is often used in scientific research and medical applications.
氦气常用于科学研究和医疗应用。