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.

Tobacco companies account for ____ of the five biggest billboard advertisers in the country.
four

Most healthy men experience about three to ____ erections in their sleep each night.
five

Vision tends to improve until it stabilises around the age of ____ or six.

five

