1.I will write to you if I have time.
2.You won't do well in the test if you don't learn your vocabulary.
3.If they don't leave now, they won't catch the plane.
4.If I get home late , my father will be angry.
5.We don't want dinner if we have a meal on plane.
6.If the parcel arrives while you're out,I will sing for it.
7.He won't go to the party if she doesn't go.
8.If you come round tomorrow evening ,I will introduce you to my cousin.
9.If you take the CD backt to the shop, they will exchange it for another .
10.If you save some money every month, you will have enough to an by Ipod.
11.I will be hungry on the journey if I don't take a sandwitch with me.
12.We won't get lost if we buy a map.