1. If you knew how unpopular Jason was, you wouldn't have invited him to the party.
2. If you don't warn your friend not to put so many tins into the plastic bag, it will break.
3. If you don't have a pen, you won't be able to write down the adress.
4. If you would have started your project earlier, you wouldn't have been so far behind now.
5. If your friend needs help, tell her to give you a ring.
6. The fan comes on if the door is opened.
