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: Light chains exist in ____ classes, lambda and kappa.

SOLUTION: two

PROBLEM: Fitness has ____ components, aerobic and muscular.

SOLUTION: two

PROBLEM: Chlorination is necessary for ____ reasons.

SOLUTION:
two