THE TYPES OF CONDITIONAL SENTENCES

 Conditional sentences (if-clauses, main clauses)

* The conditional sentences are sometimes confusing for learners of English.

Watch out:
1) Which type of the conditional sentences is used?
2) Where is the if-clause (e.g. at the beginning or at the end of the conditional sentence)?
There are three types of the if-clauses.

1- The Zero Conditional:

(if + present simple, ... present simple)
* When we talk about things that are generally or always true, we can use:
- If/When/Unless plus a present form PLUS present simple or imperative.examples:
- If he gets there before me, ask him to wait.
- When you fly budget airline, you have to pay for your drinks and snacks.
- Unless you need more space, a small car is big enough for one person.
* Notice that 'unless' means the same as 'if not'.
* We can make a zero conditional sentence with two present simple verbs (one in the 'if clause' and one in the 'main clause'):
If + present simple, .... present simple. examples:
If people eat too much, they get fat.
People die if they don't eat.

2- The First Conditional:
(if + present simple, ... will + infinitive)
* We use the First Conditional to talk about future events that are likely to happen.example:
- If it rains, I won't go to the park.
* The 'if' clause can be used with different present forms.examples:
- If I see her, I'll tell her.
- If he's feeling better, he'll come.
- If they haven’t heard the good news yet, I'll tell them.
* The "future clause" can contain 'going to' or the future perfect as well as 'will'. examples:
- If I see him, I'm going to tell him exactly how angry I am.
- If we don't get the contract, we'll have wasted a lot of time and money.

* The "future clause" can also contain other modal verbs such as 'can' and 'must'. examples:
- If you go to New York, you must have the cheesecake in Lindy's.
- If he comes, you can get a lift home with him.
* First vs. Zero Conditional:
-The first conditional describes a particular situation, whereas the zero conditional describes what happens in general.
-For example (zero conditional): if you sit in the sun, you get burned (here I'm talking about every time a person sits in the sun - the burning is a natural consequence of the sitting)
-But (first conditional): if you sit in the sun, you'll get burned (here I'm talking about what will happen today, another day might be different)

3- The Second Conditional:
(if + past simple, ... would + infinitive)

* we can use it to talk about things in the future that are probably not going to be true. Maybe I'm imagining some dream for example.
- If I had millions dollars, I'd give a lot to charity.
Note that after I / he/ she /it we often use the subjunctive form 'were' and not 'was'. (Some people think that 'were' is the only 'correct' form but other people think 'was' is equally ‘correct’.) example:
- If she were happy in her job, she wouldn't be looking for another one.
we can use it to talk about something in the present which is impossible, because it's not true. Is that clear? 

Have a look at the examples:
- If I had his number, I would call him. (I don't have his number now, so it's impossible for me to call him).
* Note the form 'If I were you' which is often used to give advice.example:
- If I were you, I wouldn't go out with that man.

* Note that the main clause can contain 'would' 'could' or 'might.
- If I had the chance to do it again, I would do it differently.
- If we met up for lunch, we could go to that new restaurant.
- If I spoke to him directly, I might be able to persuade him.
* Also note that sometimes the 'if clause' is implied rather than spoken.
- What would I do without you? ("if you weren't here")
- Where would I get one at this time of night? ("if I wanted one")
- He wouldn't agree. ("if I asked him")

* First vs. Second Conditional:
- How is this different from the first conditional?
-This kind of conditional sentence is different from the first conditional because this is a lot more unlikely.
- For example (second conditional): 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)
- But (first conditional): If I have enough money, I'll buy some new clothes (It's much more likely that I'll have enough money to buy some clothes).

4- The Third Conditional
(if + past perfect, ... would + have + past participle)
* We can use the Third Conditional to talk about 'impossible' conditions, impossible because they are in the past and we cannot change what has happened.examples:
- If I had gone to bed early, I would have caught the train.
- 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
* Notice that the main clause can contain 'would', 'could' or 'might.
If I had seen him at the meeting, I would have asked him. (But he wasn't there so I didn't.) examples:
- If I had seen him at the meeting, I could have asked him. ( But he wasn't there so it wasn't possible.)
- If I had seen him at the meeting, I might have asked him. (But I'm not sure. Perhaps if the opportunity had arisen.)
- If I had paid more attention in class, I would have understood the lesson.

* Also notice that sometimes the 'if clause' is implied rather than spoken.examples:
- I'd have done it. ("if you had asked me but you didn't.")
- I wouldn't have said that. ("if I'd been there.")
- He wouldn't have let him get away with that. ("if he had tried that with me.")

Thanks for reading !!