18. Last Saturday, it was raining heavily, so the referee decided not to start the football match. The referee decided to CANCEL because it was raining heavily.

Решение:

Необходимо дополнить предложение, сохранив смысл.

1. Last Saturday, it was raining heavily, so the referee decided not to start the football match.
2. The referee decided to cancel the football match because it was raining heavily.

Ответ: cancel the football match