Question

It's made of metal or plastic. It's used for telling the time. It's made of leather. It's used for keeping trousers up. It's made of wax. It's used for lighting a room.

Answer 1

1) the clock 2) a belt 3) a candle

Answer 2

The first item you described, made of metal or plastic and used for telling the time, is most likely a watch or a clock.

The second item, made of leather and used for keeping trousers up, is a belt.

The third item, made of wax and used for lighting a room, is a candle.