Given a sentence, fill out the missing word with a 'no' or a number (between zero and ten). You should write the numbers with english alphabet, like: four instead of 4.

[Q]: Carbon atoms are tetravalent, and therefore, can have ____ bonding pairs around each carbon atom.
[A]: four


[Q]: Children can age an adult faster than ____ years in prison.
[A]: ten


[Q]: Some children start asking questions when they're ____ or five years old.
[A]:
four