TASK DEFINITION: In this task, find the most appropriate number to replace the blank (indicated with _ ) and express it in words.
PROBLEM: Blood pressure is really _ measurements, systolic and diastolic.

SOLUTION: two

PROBLEM: Terrorism is a problem which has troubled the international community for more than _ decades.

SOLUTION: three

PROBLEM: Man therefore has _ different substances interacting with each other.

SOLUTION:
two