Conditional Clause

if

If you travel all over the world, you'll see a lot of fascinating places.

He will become rich and famous if he tries hard enough.

unless = if ... not

I'll go swimming tomorrow unless it's cold. I'll go swimming tomorrow if it's not cold.

In case

In case expresses the idea that something probably won't happen, but it might.

I'll make a cake in case someone drops in at the weekend.

=> Perhaps someone will drop in at the weekend; I'll make a cake now, whether someone comes or not; then I'll already have the cake.

If expresses possible condition, the main clause expresses result.

I'll make a cake if someone drops in at the weekend.

=> Perhaps someone will drop in at the weekend. If someone comes, I'll make a cake. But only then, not now.

provided (that) / providing (that) / as (so) long as / only if

express the idea that there is only one condition that will cause a particular result.

He can go to university	provided (that)	he gets a scholarship.
	providing (that)
	only if
	as (so) long as

NOTE: When only if begins a sentence, the subject and the verb of the main sentence are inverted. Only if it rains will we stay at home.

BUT: We'll stay at home only if it rains.

Exercise 31. Write these sentences, putting the verbs in brackets into the Present Simple or the Future Simple.

Example: If the train is (be) late, we 'II walk (walk).

1. If this suitcase _ (cost) too much, I _ (buy) a smaller one.

2. I _ (go) to the party provided you _ (go) too.

3. What _ we (do) in case the taxi _ (not/come)?

4. Mark _ (be) upset if you _ (not/come) to see him off.

5. I _ (let) you use my car as long as you _ (drive) carefully.

6. I _ (not/have) a party if I _ (fail) my exam.

7. Your parents _ (be) angry unless you _ (get) home early.

Exercise 32. Rewrite the following sentences using unless.

Example: I won't stay in the hostel if it doesn't rain. - I won't stay in the hostel unless it rains.

1. You won't speak fluent English if you don't practise.

2. You won't have a driving license if you are not at least sixteen years old.

3. Jill won't pass her exams if she doesn't study hard enough.

4. They will be late for the train if they don't hurry.

5. The children will go to the zoo if it's not cold.

Exercise 33. Complete the following sentences with if or in case. Prove your choice.

Example: We'll visit Robert if we have some free time.

(We'll probably have some free time. If we do, we'll visit Robert.)

I'll take my umbrella in case it rains later on.

(It will probably rain later on. I will take my umbrella now whether it rains or not: because if it rains, I don't want to get wet through in the rain.)

1. _ you see Marina, give her a message for me, please.

2. Will she go to college _ she has good grades in her exams?

3. Bob will ring me _ there're any problems.

4. We'll close all the windows _ it rains while we're out.

5. Take some sandwiches _ you get hungry.

Exercise 34. Choose the correct or the most suitable answer А, В or C.

Example: We'll have a picnic tomorrow A it rains.

A) unless; B) provided; C) when.

1. ___ you don't wear your coat, you'll be cold.

A) Unless; B) In case; C) If.

2. You can borrow my camera _ you're careful with it.

A) till; B) as long as; C) after.

3. ___ I win this lottery, will I go on a round-the-world cruise.

A) If; B) Only if; C) In case.

4. I'll take enough food _ I get really hungry.

A) in case; B) if; C) as soon as.

5. I'll clear my teeth _ I comb my hair.

A) when; B) as long as; C) if.

6. I'll be waiting for him _ he returns from the expedition.

A) so long as; B) until; C) unless.

7. I'm going to Bristol in the morning this afternoon. I'll ring you _ I get there.

A) if; B) when; C) until.

8. I'll see you on the 6.30 bus _ I get up early enough!

A) when; B) after; C) if.

9. They'll go to the zoo _ they get ready for their tomorrow's test.

A) till; B) after; C) in case.

10. I'll join you _ I finish this job.

A) as soon as; B) unless; C) until.

11. In Britain you can marry at the age of sixteen _ you have your parents' permission.

A) providing; B) unless; C) when.

12. _ you tell the truth, everything will be all right.

A) Unless; B) Provided; C) Only if.