Introduction. Conditional Sentences

Plan.

CONDITIONAL SENTENCES

1. The meaning of conditional sentences

2. Conditional type 0

3. Conditional type 1

4. Conditional type 2

5. Conditional type 3

6. The ways to replace “if”

(The meaning of conditional sentences)

A conditional sentence (or “conditional” for short) is commonly composed of two parts: conditional clause + main clause. Despite the many possible sequences of verb forms are conditionals, the following four types represent perhaps the commonest and the most useful ones:

- If you heat ice, it melts.

- If we catch the 10 o’clock train, we will get there by lunchtime.
- If we caught the 10 o’clock train, we would get there by lunchtime.
- If had caught the 10 o’clock train, we would have got there by lunchtime.

IMPORTANT:

- We can reverse the order: If it rains, I will stay at home / I will stay at home if it rains.

- We write a comma (,) after the if-clause, when we begin with the if-clause.

There are four types of Conditional Sentences. Each type contains a different pair of tenses. With each type certain variations are possible.

2. TYPE O: GENERAL CONDITION.

The 0 (zero) conditional is the easiest to understand! It is also called the real or factual conditional because it is used to talk about facts, or something that is always true.

If / unless

Subject

Present tense

Subject

Present tense

If I eat too much, I get sick.

The result [ I get sick ] is always true of the condition [ if I eat too much ]. It is a fact! There is a fixed connection between the two events.

This conditional is easy because we don’t have to remember which clause goes where or which verb tense is used, we just have to remember:

§ facts, habits, daily routines, rules, general truths = present simple

Every day I take the train to work. If I miss the train, I drive to work.

If-clause à Present Simple

Main-clause à Present Simple

e.g.: If you eat too much, you feel bad.

If I don´t get enough sleep, I feel tired.

If you mix yellow and blue, you get green.

We use this structure to talk about habits and general truths.

Here if = whenever

We can also use modals in the result clause:

I can’t drive if I don’t have my glasses.

If you want to go to university, you must study hard.

If you want to lose weight, you should eat less and exercise more.

You can’t drive a car if you don’t have a license.

WE can also use the imperative in the result clause

If you drink, don’t drive.

Please don’t disturb me if I am asleep!

If you’re hungry, eat something!

Notice that 'unless' means the same as 'if not'.

• Unless he asks you politely, refuse to do any more work on the project.
• Unless prices are rising, it's not a good investment.

3. TYPE 1: REAL CONDITION

This type of condition shows that it is still possible for the event or the action to happen. It is called “ Conditional Clause- Type 1”.

If/when/unless

Subject

Present tense

Subject

Will Can May

Infinitive verb without “to”

- If the weather is bad, we will cancel the meeting.

- We will cancel the meeting if the weather is bad.

- If my friend invites me, I’ll visit him.

- I will visit my friend if he invites me.

Unless = [ If + not ]

If you don’t study hard, you’ll fail.

Unless you study hard, you’ll fail.

You’ll fail unless you study hard.

There is a difference between If and When?

Study the following 2 conditional clauses:

A) If he comes, I will tell him the truth.

B) When he comes, I will tell him the truth.

When we use if, we are not sure about the event to happen or not.

But when we use when we are sure about the event to happen. So, in (B) we are sure that he will come. But in (A) we are not sure about his coming.

Variations to Type 1:

4. TYPE 2: UNREAL CONDITION

This type of condition shows that it is impossible for the event or the action to happen. It is called “ Conditional Clause- Type 2 ”.

If / unless

Subject

Past tense

Subject

Would Could Might

Infinitive verb without “to”

- If I were you, I wouldn’t waste my time. [ Used to give advice ]

- If the weather was/ were bad, we would cancel the meeting.

- We would cancel the meeting if the weather was/ were bad.

-If they have enough time, they will finish the work. [ Type 1 ]

-Unless they have enough time, they will not finish the work.

-If they had enough time, they would finish the work. [ Type 2 ]

-Unless they had enough time, they would not finish the work.

-If he didn’t go, he could be punished.

-Unless he went, he could be punished.

Variations to Type 2:

5. TYPE 3: IMPOSSIBLE OR CONTRARY TO FACT CONDITION

This type of condition shows that it is contrary to fact. It is called “ Conditional Clause- Type 3 ”.

If/unless

Subject

Past perfect Had + 3^rd form

Subject

Would have Could have Might have

3^rd form

- If the weather had been bad, we would have canceled the meeting.

- We would have canceled the meeting if the weather had been bad.

Here the meaning implies that we didn’t cancel the meeting and the weather was fine and not bad.

- If they have enough time, they will finish the work. [ Type 1 ]

- If they had enough time, they would finish the work. [ Type 2 ]

- If they had had enough time, they would have finished the work. [ Type 3 ]

Variations to Type 3:

6. IF CAN BE REPLACED BY:

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