1.
If Harry doesn't phone, we'll leave without him.
Unless Harry phones, we'll leave without him.
2.
Unless Sheila returns the money she owes me, I won't be able to pay my rent.
If Sheila doesn't return the money she owes me, I won't be able to pay my rent.
3.
Sarah will be disappointed if you don't send her a birthday card.
Sarah will be disappointed unless you send her a birthday card.
4.
Maria won't go to the theatre if Peter doesn't go with her.
Maria won't go to the theatre unless Peter goes with her.
5.
If you don't pay the electricity bill, it will be cut off.
Unless you pay the electricity bill, it will be cut off.
6.
Unless Kate comes home soon, her parents will call the police.
If Kate doesn't come home soon, her parents will call the police.
7.
If the children don't behave themselves, they won't go to the zoo.
Unless the children behave themselves, they won't go to the zoo.
8.
Unless my mother offers to help me, I won't have time to make all the preparations.
If my mother doesn't offer to help me, I won't have time to make all the preparations.
9.
Unless you tidy your room, I won't take you to the party.
If you don't tidy your room, I won't take you to the party.
10.
If Dennis doesn't write soon, I will be very upset.
Unless Dennis writes soon, I will be very upset.
