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]: Natural ytterbium is a mixture of ____ stable isotopes, with seven other unstable isotopes known.
[A]: seven


[Q]: Female smokers enter menopause an average of ____ years earlier than nonsmokers.
[A]: five


[Q]: Most corporate bonds have a maturity of ____ years or less.
[A]:
five