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: Couples spend ____ billion dollars a year on infertility treatments.

A: two
****
Q: Fats come in ____ different forms saturated and unsaturated.

A: two
****
Q: Democratic elections take place every ____ years.

A:
six
****