TASK DEFINITION: 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.
PROBLEM: Manatees swim ____ to six miles per hour.

SOLUTION: two

PROBLEM: Calves are born after a gestation of ____ months.

SOLUTION: nine

PROBLEM: Doctors spend ____ years in medical school, so they're experts on human anatomy.

SOLUTION:
four