Tom balonu helyum ile doldurdu.
- Tom filled the balloon with helium.
Helyum, neon, argon, kripton, ksenon ve radon soy gazlardır.
- Helium, neon, argon, krypton, xenon and radon are noble gases.
... They fuse hydrogen into helium, helium into lithium, ...
... the universe needs more to work with than just hydrogen and helium. ...