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 women experience a labor of three to ____ days.
[A]: five


[Q]: China has about one in ____ of all smokers in the world.
[A]: four


[Q]: Snakes have ____ layers of skin.
[A]:
three