Contitional sentences (0)

Conditionals
Sentences with if are used to express possibilities.
0 Zero conditional
If- clause  present (past) simple
Main clause  present (past) simple
Sometimes sentences with if express certainty rather than possibility. The zero conditional is used to talk about sth. that is always true ( such as a scientific fact ), or that was always true in the past. In this type of conditional we can use when instead of if.
E.g., If/When you mix blue and red, you get purple .
If/When you don’t water flowers, they die.
(present simple in both parts of the sentence)
If/When I asked her to come with us, she always said no.
(past simple in both parts of the sentence)
1 First conditional
If-clause  present simple;
Main clause  future tense (or: can, must, may, etc., + bare infinitive )
Used to talk about the consequences of a possible action (a real or very probable situation in the present or future).
E.g., If I write my essay this afternoon,
I will have time to go out tonight . (or: I might go out tonight).
(It is still morning , and it is quite possible that I will do this.)
NOTE : With type 1 conditionals we can use unless + affirmative verb (= if + negative verb).
E.g., I will not be able to come unless Joe gives me a lift. (= If Joe does not give me a lift, ...)
Provided that/ providing that are synonyms for if that can be used with type 1 conditionals.
2 Second conditional ( unreal present)
If-clause  past simple/past continuous ;
Main clause  conditional tense (would, could , might + present bare infinitive)
Used to talk about the consequences of a hypothetical action (imaginary situations that are contrary to facts in the present, and therefore are unlikely to happen in the present or the future).
E.g., If I wrote my essay this afternoon,
I would have time to go out tonight.
(It is still morning, but I think it is less likely that I will do this.)
We can use either was or were for I, he, she, it in the if-clause. We can also use the structure If I were you... to give advice .
E.g., If I were you,
I would tell her the truth .
3 Third conditional (unreal past)
If-clause  past perfect /past perfect continuous;
Main clause  conditional perfect tense (would, could, might + perfect bare infinitive)
Used to talk about the possible consequence of an action that did not happen (imaginary situations that are contrary to facts in the past). Also used to express regrets or criticism.
E.g., If I had written my essay this afternoon,
I would have had time to go out tonight.
(It is now evening , and I haven ’t written my essay: it is now impossible for me to go out.)
E.g., If I hadn’t been working today , we would have gone to the beach .
Mixed conditionals
We can form mixed conditionals (if the context permits it) by combining an if-clause from one type with a main clause from another .
If-clause
Main clause
Type 2
If he came back late last night ,
Type 1
he won’t be on time for work today.
Type 2
If you were polite ,
Type 3
you wouldn’t have talked to him like that.
Type 3
If he hadn’t missed the bus,
Type 2
he would be here now.
Wishes
We can use wish / if only to express a wish.
Verb tense
Example
Use
Wish / if only
+ past simple/
past continuous
I wish I was on holiday now. (but I’m not)
If only I were going with them . (but I’m not)
To say that we would like sth. to be different about a present situation
Wish / if only
+ past perfect
I wish I had passed the exams . (but I didn’t)
If only she hadn’t cheated me. (but she did)
To express regret about sth. that happened or didn’t happen in the past
Wish / if only
+ subject + would + bare inf.
I wish you wouldn’t talk with your mouth full .
If only it would stop snowing.
To criticise other people or complain about a situation now, in the future or generally.
I.e., to express:

• A polite imperative
  
• A desire for a situation or person’s behaviour to change
  

Wish + could
I wish I could come with you to that concert next week.
To express hypothetical ability or permission now, in the future or generally
NOTE:

• If only is used in exactly the same way as wish, but it is more emphatic or more dramatic.
  
• We can use were instead of was after wish and if only. E.g., I wish I were/was on holiday now.
  

The Unreal Past
A past tense does not always refer to past time. In some sentences and with certain verbs or phrases we use a past tense to refer to the present or the future or to a general situation.

The past simple can be used to refer to the present when we talk about imaginary, unreal or impossible situations that are contrary to facts in the present.
The past simple is used with:

• Type 2 conditionals – If he had money , he would move into a bigger flat.
  
• Suppose /supposing – Suppose/Supposing he lied to you, what would you do?
  
• What if – What if life existed on other planets?
  
• Wish/if only – I wish/If only I had more space.
  
• Would rather (present) – I’d rather you left now.
  
• As if/as though – Nancy acts as if/as though she owned the place .
  
• It’s (about/high) time – It’s (about/high) time you went to bed.
  

The past perfect can be used to refer to imaginary, unreal or impossible situations that are contrary to facts in the past.
The past perfect is used with:

• Type 3 conditionals – If he hadn’t been so slow , he wouldn’t have lost the race .
  
• Suppose/supposing – Suppose/Supposing you had been in a position to help, would you have done so?
  
• Wish/if only – I wish/If only I hadn’t hurt her.
  
• Would rather (past) – I’d rather you had not revealed our secret .
  
• As if/as though – He spoke about Maradona as if/as though he had been a personal friend .
  

Had better/Would rather

Had better (= it would be good to) is used to give strong or urgent advice. Had better cannot be used in the past or the comparative .

• had better + bare infinitive  immediate future
  You had better ask for help.
  

Would rather (= would prefer to) expresses preference.
When the subject of would rather is also the subject of the following verb, we use the following constructions:

• would rather + present bare infinitive  present/future
  I’d rather tell you now.
  
• would rather + perfect bare infinitive  past
  I went out last night but I’d rather have stayed in.
  
• Would rather + bare infinitive + than + bare infinitive
  Since it’s such a beautiful day, I’d rather go to the park than watch TV.
  

When the subject of would rather is different from the subject of the following verb, we use the following constructions:

• would rather + past tense  present/future
  I’d rather Susan lived with us.
  
• would rather + past perfect  past
  I’d rather we had left earlier, then we wouldn’t have been caught in the rush hour traffic .