1. If I hadn't been waiting for the cheque for a long time, I wouldn't be thinking about leaving some money on the table and walking out.
2. If there's an emergency, you have this money saved (ou "should there be an emergency, you have this money saved" - essa opção é melhor, na minha opinião).
3. I only ever buy a car, regardless of model, if my brother approves of it.
4. I don't buy things if I can't get a discount.
5. If I had the money, I'd buy this dress.
6. I'm only taking you to the mall if you promise not to ask me to buy any toys.
