Conditional Tenses

Conditional sentence is divided into two clauses, they are; if clause (dependent clause) and main clause (independent clause). There are 3 types of the conditional sentence: type I, type II and type III.

Conditional Sentences which are also called conditional tenses are also known as Conditional Clauses or If Clauses. They are used to express that the action in the main clause (without if) can only take place if a certain condition (in the clause with if) is fulfilled.

Conditional Sentence Type 1
→ It is possible and also very likely that the condition will be fulfilled (real possibility).
It is called type I because it uses V1 (infinitive).

Form: if + Simple Present, Simple future (will-Future)

Example: If I drink coffee tonight, I will be hard to sleep.
                       

The main clause can also be at the beginning of the sentence. In this case, don't use a comma.

Example: I will be hard to sleep if I drink coffee tonight.

Note:
Main clause and / or if clause might be in  negative form.

Example: If I don’t see him this afternoon, I will phone him in the evening.

Use:
The conditional Sentences Type I refer to the future. An action in the future will only happen if a certain condition is fulfilled by that time. We don't know for sure whether the condition actually will be fulfilled or not, but the conditions seems rather realistic – so we think it is likely to happen.

Example: If I find her address, I’ll send her a wedding invitation.

I want to send a wedding invitation to a friend. I just have to find her address. I am quite sure, however, that I will find it.

Example: If John has the money, he will buy a big red Mercedes.

I know John very well and I know that he earns a lot of money and that he loves a big red Mercedes. So I think it is very likely that sooner or later he will have the money to buy a big red Mercedes.


Conditional Sentence Type 2
→ It is possible but very unlikely, that the condition will be fulfilled (unreal possibility) or
just as subjunctive.
It is called type II because it uses V2 (past tense).

Form: if + Simple Past, Past future / Conditional I (= would + Infinitive)

Example: If I drank coffee tonight, I would be hard to sleep.
                       

The main clause can also be at the beginning of the sentence. In this case, don't use a comma.

Example: I would be hard to sleep if I drank coffee tonight.

Note:
 Main clause and / or if clause might be negative.

Example: If I had a lot of money, I wouldn’t stay here.

Were instead of Was
In IF Clauses Type II, we usually use ‚were‘ – even if the pronoun is I, he, she or it –.

Example: What would you do if you were me?
                 If I were you, I would not do that.

Use:
The conditional Sentences Type II refer to situations in the present. An action could happen if the present situation were different. I don't really expect the situation to change, however. I just imagine „what would happen if …“

Example: If I found her address, I would send her a wedding invitation.

I would like to send a wedding invitation to a friend. I have looked everywhere for her address, but I cannot find it. So now I think it is rather unlikely that I will eventually find her address.

Example: If John had the money, he would buy a big red Mercedes.

I know John very well and I know that he doesn't have much money, but he loves a big red Mercedes. He would like to own a big red Mercedes (in his dreams). But I think it is very unlikely that he will have the money to buy one in the near future.


Conditional Sentence Type 3
→ It is impossible that the condition will be fulfilled because it refers to the past (impossibility).
It is called type III because it uses V3 9past participle).

Form: if + Past Perfect, Conditional II (= would + have + Past Participle)

Example:  If I had drunk coffee last night, I would have been hard to sleep.
                               

The main clause can also be at the beginning of the sentence. In this case, don't use a comma.

Example: I would have been hard to sleep if I had drunk coffee last night.

Note: 
Main clause and / or if clause might be negative.

Example: If I hadn’t studied, I wouldn’t have passed my exams.

Use:
The conditional Sentences Type III refer to situations in the past. An action could have happened in the past if a certain condition had been fulfilled. Things were different then, however. We just imagine, what would have happened if the situation had been fulfilled.

Example: If I had found her address, I would have sent her a wedding invitation.

Sometime in the past, I wanted to send a wedding invitation to a friend. I didn't find her address, however. So in the end I didn't send her an invitation.

Example: If John had had the money, he would have bought a big red Mercedes.

I knew John very well and I know that he never had much money, but he loved a big red Mercedes. He would have loved to own a big red Mercedes, but he never had the money to buy one.

Other conditional tenses:

1. THE ZERO CONDITIONAL (Certainty / General truth)
The zero conditional is used for when the time being referred to is now or always and the situation is real and possible. The zero conditional is often used to refer to general truths. The tense in both parts of the sentence is the simple present. In zero conditional sentences, the word "if" can usually be replaced by the word "when" without changing the meaning.

Form: if + Simple Present, Simple present

Example: If I drink coffee tonight, I am hard to sleep.

                If this thing happens, that thing happens.

                If you heat ice, it melts.
             
                If it rains, the grass gets wet.

2. MIXED TYPE CONDITIONAL (An unreal past condition and 
    its probable result in the present).
The mixed type conditional is used to refer to a time that is in the past, and a situation that is ongoing into the present. The facts they are based on are the opposite of what is expressed. The mixed type conditional is used to refer to an unreal past condition and its probable result in the present. In mixed type conditional sentences, the if clause uses the past perfect, and the main clause uses the present conditional.

Form: If + past perfect or simple past                   present conditional or perfect conditional

Example: If this thing had happened that thing would happen. (but this thing didn't happen
                so that thing isn't happening)
             
                If I had worked harder at school I would have a better job now.

                If we had looked at the map we wouldn't be lost.

                If you weren't afraid of spiders you would have picked it up and put it outside.

See also; its exercise.