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.

Sexual maturity is reached within ____ to four years.
two

Seraphs have ____ wings, and their voices can shake doorposts and thresholds.
six

Antibiotic therapy is usually necessary for up to ____ weeks to control infection.

three