TASK DEFINITION: In this task, find the most appropriate number to replace the blank (indicated with _ ) and express it in words.
PROBLEM: Reverse osmosis uses three to ten gallons of water to produce _ gallon of drinking water.

SOLUTION: one

PROBLEM: Females reach sexual maturity around four to _ year-olds.

SOLUTION: five

PROBLEM: Most dens are oval shape, six to _ feet long and about six feet in height and width.

SOLUTION:
nine