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: Acoustic instruments consist of ____ main parts neck, top, back and sides.

SOLUTION: four

PROBLEM: Many people have ____ symptoms until they suffer chest pains or a heart attack.

SOLUTION: no

PROBLEM: Cytochrome oxidase consists of two cytochromes and ____ copper atoms.

SOLUTION:
two