1. If one (presses) this button, one gets boiling
water.
2. After finishing all
activities, you should make sure that you have (unplugged) all the appliances.
3. If there is a
danger of fire, they always (cut off)
electricity.
4. The first thing you
have to do when you want to start it is (to
plug in) the cord to the socket.
5. If it is still too
cold, you have to (switch on) the
heater.
6. They usually (fit in) the equipment with extra safety
system.