`13`. The only reason Jimmy oftens gets marks is because he is lazy
=> If Jimmy weren't lazy, he wouldn't often get marks.
`14`. We get lost because we don't have a map.
=> If we had a map, we wouldn't get lost.
`15` .We don't go on holiday because we don't have enough money
=> If we had enough money, we would go on holiday.
`16`. She don't hurry, so she misses the train
=> If she hurried, she wouldn't miss the train.
`17`. I buy beef because I don't know she can't eat it.
=> If I knew she can't eat beef, I wouldn't buy it.
`18`. If you leave a forwarding address, we will be able to contact you.
=> Unless you leave a forwarding address, we won't be able to contact you.
`19`. Unless you save some money, you will never be able to buy a car
=> If you don't save some money, you will never be able to buy a car.
`20`. The boys don't have any matches, so they can't light the fire.
=> If the boys had matches, they could light the fire.
`21`. The new car is so expensive that he can't buy it
=> If the new car weren't so expensive, he could buy it.