1 You can't visit the United State unless you get the visa.
-> If you got a visa, you could visit the United States.
2 Unless someone has a key, we can't get into the house.
-> We can only get into the house if someone has a key.
3 You will catch a cold if you don't keep your feet dry.
-> Unless you keep your feet dry, You will catch a cold
4 Joan will stay on at school unless she finds a good job before September.
-> If she finds a good job before September ,Joan won't stay on at school.
5 If it doesn't rain soon, millions of pound's worth of crops will be lost.
-> Unless it rain soon,millions of pound's worth of crops will be lost.
6 It's too cold, we can't go jogging.
-> If it were warmer, we could go jogging
7 Jane can't get married yet, she is too young.
-> If Jane were older, she could get married
8 Mary is too short, she can't take the bos on the shelves.
-> If mary were higher, she could take the bos on the shelves
9 Mrs Smith is too old, she can't take exercise every day.
-> If Mrs Smith were younger, she could take exercise every day.
10 The house is too expensive for us to buy
-> If the house were cheapper, we could buy it
11 Henry regretted buying the second-hand car.
-> Henry wished he had bought the second-hand car.
12 I'll call the police if you don't leave me alone.
-> Unless you leave me alone, I'll call the police _______________________________
13 Don't run fast or you will feel tired.
-> If you run fast, you will feel tired.
14 Make me some coffee, and I'll make some toasts for you.
-> If you make me some coffee, I'll make some toasts for you.
15 In the snowy weather we don't go to school.
-> If it snows, we won't go to school.__________________________________
16 Why don't you take the bus? That's what I would do.
-> If I were you, I'd take the bus
17 Imagine that you were rich. What would you do?
-> What would you do If you were rich?
18 I didn't have an umbrella with me and so I got wet.
-> I wouldn't have got wet if I had had an umbrella
19 Without your help, I wouldn't have been able to move the furniture.
-> If you hadn't helped me, I wouldn't have been able to move the furniture
20 Peter didn't leave early, so he missed the last train.
-> If Peter had left early, he wouldn't missed the last train.