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


[Q]: Colostrum is bright yellowish thick milk secreted in the first ____ to six days after birth.
[A]: three


[Q]: Plasma levels fall by about a half within ____ to four hours.
[A]:
three