3. Conjunctions introducing conditional clauses

3.1. Different meanings of if

The conditional clauses in all the examples so far have begun with if. If can vary in its meaning.

In Type 0, if is closely related in meaning to when(ever):

If I make a promise, I keep it. =

When I make a promise I keep it.

In some cases, if corresponds closely to as, since, or because (clause of reason)

If (as you say) you haven't done the homework, you won't be able to follow this lesson.

If can also mean although (concessive-type clause):

If you know the answer, nobody else does.

= Although you may know the answer, nobody else does.

If meaning although is often used with adjectives.

The room was well-furnished, if a little badly decorated.

3.2. Other conjunctions commonly used to introduce 'true' conditional clauses are illustrated in the following sentences:

provided /providing (that)/ on (the) condition( that)

so long as / as long as

We use these conjunctions to emphasize that the condition is necessary to the result. They all mean only if and can only be used with real conditions.

You can borrow my notes on condition (оr provided) that you give them back to me tomorrow.

I'll do what you say provided the police are not informed.

You can come with us, so long as (or as long as) you don't make a nuisance of yourself.

suppose / supposing(that) / assuming (that) / What if

We use these conjunctions to speak about imaginary conditions

Suppose (оr supposing) you told him the truth, what could he do about it?

Assuming (that) it is fine tomorrow, we’ll go for a swim

What if the money doesn’t arrive on time.

We use even if to express a condition that is unexpected in the circumstances.

Even if it rains, we'll still go for a picnic.

in case introduces a future possibility against which a precaution is needed in advance. The difference between in case and if illustrated in the following two sentences:

a I'm taking an umbrella in case it rains later on. (I take it whatever the weather is like now)

b I'll take an umbrella if it rains later on. (I will only take it only if it begins to rain)

We use whether … or not to express alternative conditions

They will deliver the furniture whether there is someone to receive it or not.

3.3. Negative conditions

3.3.1 Unless

Unless often has the same meaning as if... not, and we can often use either

There's no chance of you getting the job unless you apply, (or ...if you don't apply.)

You can't travel on this train unless you have a reservation, (or...if you don't have...)

Unless it rains, I'll pick you up at 6.00.

However, there are contexts where the forms are not interchangeable.

We prefer to use unless

- to make the sentence more emphatic (means except for, only if not)

Unless you change your mind I won’t be able to help you.

- for introducing clauses that contain other negative elements

Don't ask me to explain unless you really don't understand.

- to introduce an afterthought

Without Philip to run it, the course can't continue - unless you want the job, of course.

In written English, the afterthought is often separated from the rest of the sentence by a dash.

we use if...not (but not unless):

-in most unreal conditional sentences:

He would be happier if he didn't take things so seriously, (not ...unless he took...)

If she hadn't gone to university, she would have gone into the police force, (not Unless she had gone...)

- when we talk about emotions:

I'll be amazed if Christie doesn't win. (not …unless Christie wins.)

- when the negative condition after if is contrary to known facts

You’d be happier if you didn’t have such high expectations.

- in most questions:

If you don't pass the test, what will you do? (not unless you pass...)

What time shall we leave for the theatre if he doesn’t turn up?

3.3.2. if it was/were not for + noun

We use if it was/were not for + noun to say that one situation is dependent on another situation or on a person.

If it wasn't/weren't for Vivian, the conference wouldn't be going ahead.

If it weren't for Jim, this company would be in a mess.

When we talk about the past we use If it had not been for + noun:

If it hadn't been for my parents, I would never have gone to university.

If it hadn't been for their goalkeeper, United would have lost.

In formal and literary language inversion is very common for this type of sentence:

Were it not for Vivian...

Had it not been for my parents...

3.3.3. but for + noun

We often use but for + noun with the same meaning as if it was/were not for + noun

But for Jim's support, I wouldn't have got the job. (= If it hadn't been for Jim...)