English Grammar. Conditional Sentences.

Conditional Sentences in English Grammar. 

Why? What? How? What if?


Section 1 - Introduction


A conditional sentence is a complex sentence with a subordinate clause of condition that usually begins with the conjunction IF.

If I go outside (subordinate clause of condition), I will get wet. (main clause)

Different Types of Conditions

  • There are different types of conditions. Some are possible or likely, others are unlikely, and others are impossible:
  1. If the weather improves, we’ll go for a walk. (It is possible or likely that the weather will improve.)
  2. If the weather improved, we could go for a walk. (It is not likely that the weather will improve.)
  3. If the weather had improved, we could have gone for a walk. (The weather did not improve – fine weather is therefore an impossible condition.)

Zero Condition

Zero Conditional

Certainty, factual implication, general fact, overall truth – the result of this condition is always the same.

Main clause: present, if clause: present.


  • Water boils if you heat it to 100 degrees Celsius.
  • It gets dark if the sun goes down.
  • A green light comes up if you press the button.
  • My boss gets angry if I’m late for work.


Rule matching

Combine two parts, so you have a conditional sentence form . 

  • 0. If + present simple,
    present simple
  • 1. If + present simple,
    will + infinitive
  • 2. If + past simple,
    would + infinitive
  • 3. If + past perfect,
    would + perfect infinitive

Section 2 - The First Conditional

Imagined conditions: the first conditional

We use the first conditional to talk about the result of an imagined future situation, when we believe the imagined situation is quite likely: 

First conditional: form

if + present simple + modal verb with future meaning (shall/should/will/would/can/could/may/might)


  • If he gets a job in Liverpool (Conditional clause), he’ll have to get up early. It’s a long drive. (Main clause)
  • If Sheila rings, I might ask her to come over for dinner.

Form First Conditional Sentences.

  • If it rains,
    I won't go to the park.
  • If I study today,
    I'll go to the party tonight.
  • If I have enough money,
    I'll buy some new shoes.
  • She'll miss the bus
    if she doesn't leave soon


We use the modal verb in the main clause, not in the conditional clause.

  • If a lawyer reads the document, we will see if we’ve missed anything important.

Not: If a lawyer will read the document…

If I will study hard, I will get a promotion.

  • Correct.
  • Wrong.
Is this sentence correct?

Section 3 - The Second Conditional

Imagined conditions: the second conditional

We use the second conditional to talk about the possible result of an imagined situation in the present or future. We say what the conditions must be for the present or future situation to be different.

Second conditional: form

if + past simple, modal verb with future-in-the-past meaning (should/would/might/could)


  • If you asked her nicely (conditional clause), she would say yes, I’m sure. (main clause)
  • If people complained, things would change. (People don’t complain at the moment.)

Form Second Conditional Sentences.

  • If I won the lottery,
    I could buy a big house.
  • She would travel all over the world
    if she were rich.
  • If I had his number,
    I would call him.
  • If I were you,
    I wouldn't go out with that man.


We use would in the main clause, not in the conditional clause:

  • If you decided to take the exam, you would have to register by 31 March.

Not: If you would decide to take the exam... 

First and second conditional compared

The First Conditional is more likely to happen. 

  • If I have enough money, I'll buy some new shoes (It's much more likely that I'll have enough money to buy some shoes)

The Second Conditional is a lot more unlikely.

  • If I had enough money I would buy a house with twenty bedrooms and a swimming pool (I'm probably not going to have this much money, it's just a dream, not very real)

Fill in the blanks.

1. He's coming to our offices tomorrow. If I (see) him, I'll give him the message. 

2. We (move)  if we had the money. Unfortunately new houses are very expensive in this area. 

3. If I (be) a millionaire, I'd still work so that I didn't get bored. 

4. If I (tell) you a secret, will you promise not to tell anyone? 

5. Do you think it would be better if I (wait) another week, or shall I sell my shares in the company now?

Section 4 - The Third Conditional

Imagined conditions: the third conditional

We use the third conditional when we imagine a different past, where something did or did not happen, and we imagine a different result:

Third Conditional Form:

if + past perfect, modal verb with future-in-the-past meaning (should/would/might/could) + have + -ed form


  • If they had left earlier (conditional clause), they would have arrived on time. (main clause)
  • If I had played better, I would have won(I didn’t play well and I didn’t win.)
  • It would have been easier if George had brought his own car. (George didn’t bring his own car, so the situation was difficult.)

Form Third Conditional.

  • If we had taken a taxi,
    we wouldn't have missed the plane
  • She wouldn't have been tired
    if she had gone to bed earlier
  • He would have been on time for the interview
    if he had left the house at nine
  • If I hadn't eaten so much,
    I wouldn't have felt sick

Mixed Conditional Exercise

  1. If you (wait) a minute, I'll come with you.
  2. If we arrived at 10, we (miss) Tyler's presentation.
  3. We (help) John if we'd known about his problems.
  4. If they (use) new batteries, their camera would have worked correctly.
  5. If I went anywhere, it (be) New Zealand.

Section 5 - Other combinations

Real Conditionals

Some conditions seem more real to us than others. Real conditionals refer to things that are true, that have happened, or are very likely to happen.


  • If you park here, they clamp your wheels. (It is always true that they clamp your wheels if, or every time, you park here.)
  • If I can’t sleep, I listen to the radio. (it is often true that I can’t sleep, so I listen to the radio)

In real conditional sentences, we can use the present simple or present continuous in both clauses for present situations, and the past simple or past continuous in both clauses for past situations. We can use these in various different combinations...


Present continuous + present simple

  • If the kids are enjoying themselves, we just let them go on playing till they’re ready for bed. (Every time this happens, this is what we do.)

Present continuous + present continuous

  • If the economy is growing by 6%, then it is growing too fast.  (If it is true that the economy is growing by 6%, then it is true that it is growing too fast.)

Past simple + past simple

  • If my father had a day off, we always went to see my granddad. (Every time that happened in the past, that is what we did.)

Past simple + past continuous

  • Kevin always came in to say hello if he was going past our house. (Every time he was going past our house, that is what he did.)

Conditional clauses with will or would

Will and would can be used in conditional clauses, either with the meaning of ‘being willing to do something’, or to refer to later results:

  • If Clare will meet us at the airport, it will save us a lot of time. (if Clare is willing to meet us)
  • If you would all stop shouting, I will try and explain the situation!
  • If it will make you happy, I’ll stay at home tonight. (If it is true that you will be happy as a result, I’ll stay at home tonight.)

We sometimes stress the will or would, especially if we doubt that the result will be the one mentioned:

  • If it really would save the planet, I’d stop using my car tomorrow. (If it really is true that the planet would be saved as a result, I would stop using my car, but I doubt it is true.)

Ranking question: will or would

  • If you
  • will
  • phone
  • the manager now,
  • he will
  • surely
  • make an appointment
  • with you.
Combine words to make a sentence. 

If + should

We can use if with should to refer to events which might happen by chance or by accident.


  • If you should bump into Carol, can you tell her I’m looking for her? (If by chance you bump into Carol.)
  • If the government should ever find itself in this situation again, it is to be hoped it would act more quickly.

Drag and Drop: If + should

Drag and Drop to form If should sentence.
  • I would be very happy
  • if he should turn up at the party.
  • If you should meet John,
  • tell him that the meeting has been postponed.

Section 6 - Test your knowledge

1. If he'd fallen from the 30th floor,

  • he died.
  • he might have died.
  • he would have died.

2. If I studied harder at school,

  • I would have a better job now
  • I will have a better job now

3. If she gets your message,

  • she'll definitely be here later.
  • she'd definitely be here later.
  • she'd have been here later.

4. If you had been in her position,

  • what would you have done?
  • what did you do?
  • what would you do?

5. If you see her tonight,

  • what would you say?
  • what will you say?
  • what would you have said?

6. If you were offered a well-paid job in another country,

  • would you have taken it?
  • would you take it?
  • will you take it?

7. If we hadn't been in such a hurry,

  • we wouldn't have forgotten the sandwiches.
  • we would have forgotten the sandwiches.
  • we didn't forget the sandwiches.

8. I'd have given her a lift

  • if I had known she needed one.
  • if I hadn't known she needed one.
  • If I knew she needed one.

9. If they received your application,

  • you'd have an answer by now.
  • you'll get an answer pretty soon.

10. What would happen if

  • I had pressed this button?
  • I pressed this button?