1) what is the compass used for? - it is used to see what direction are you heading to.
2) what is a thermometer made of? - it is usually made of glass and mercury
3) what is a vacuum cleaner used for? - to clean the house
4) What are windows made of? - they are made of glass
5) How often are the Olympic Games hold? - they are hold every 4 years
6) How often is the soccer World Cup played? - they are hold every 2 years