Why do you prevent them______playing computer games—Because they have a bad______on teenagers.

The authorities declared that because of the war petrol was _____ and had to be rationed (定量供应).

14. —- Is it Tom that playing basketball? —- It __________ be him. He is so crazy about basketball.

Usually children are allowed to ___________ when they are six years old.

It was not until midnightthey reached the camp site.[ ]