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: Sponges have ____ main tissue layers.

SOLUTION: three

PROBLEM: Neurofibromatosis appears in ____ forms.

SOLUTION: two

PROBLEM: Most apartment buildings have at least ____ exit stairways.

SOLUTION:
two