Conditional Sentences 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. There are three types of Conditional Sentences.
Conditional Sentence Type 1
→ It is possible and also very likely that the condition will be fulfilled.
Form: if + Simple Present, will-Future
Example: If I find her address, I’ll send her an invitation.
Form
if + Simple Present, will-Future
Example: If I find her address, I will send her an invitation.
The main clause can also be at the beginning of the sentence. In this case, don't use a comma.
Example: I will send her an invitation if I find her address.
Note: Main clause and / or if clause might be negative. See Simple Present und will-Future on how to form negative sentences.
Example: If I don’t see him this afternoon, I will phone him in the evening.
Use
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 an invitation.
I want to send an 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 Ferrari.
I know John very well and I know that he earns a lot of money and that he loves Ferraris. So I think it is very likely that sooner or later he will have the money to buy a Ferrari.
Conditional Sentence Type 2
→ It is possible but very unlikely, that the condition will be fulfilled.
Form: if + Simple Past, Conditional I (= would + Infinitive)
Example: If I found her address, I would send her an invitation.
Form
if + Simple Past, Hauptsatz mit Conditional I (= would + Infinitive)
Example: If I found her address, I would send her an invitation.
The main clause can also be at the beginning of the sentence. In this case, don't use a comma.
Example: I would send her an invitation if I found her address.
Note: Main clause and / or if clause might be negative. See Simple Past und Conditional I on how to form negative sentences.
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: If I were you, I would not do this.
Use
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 an invitation.
I would like to send an 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 Ferrari.
I know John very well and I know that he doesn't have much money, but he loves Ferraris. He would like to own a Ferrari (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.
Form: if + Past Perfect, Conditional II (= would + have + Past Participle)
Example: If I had found her address, I would have sent her an invitation.
Form
if + Past Perfect, Hauptsatz mit Conditional II
Example: If I had found her address, I would have sent her an invitation.
The main clause can also be at the beginning of the sentence. In this case, don't use a comma.
Example: I would have sent her an invitation if I had found her address.
Note: Main clause and / or if clause might be negative. See Past Perfect and Conditional II on how to form negative sentences.
Example: If I hadn’t studied, I wouldn’t have passed my exams.
Use
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 an invitation.
Sometime in the past, I wanted to send an 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 Ferrari.
I knew John very well and I know that he never had much money, but he loved Ferraris. He would have loved to own a Ferrari, but he never had the money to buy one.
Exceptions
Sometimes Conditional Sentences Type I, II and III can also be used with other tenses.
Conditional Sentences Type I (likely)
| Condition refers to: | IF Clause | Main Clause |
| future action | Simple Present | If the book is interesting, … | Future I | …I will buy it. |
| Imperative | …buy it. |
| Modal Auxiliary | …you can buy it. |
| action going on now | Present Progressive | If he is snoring, … | Future I | …I will wake him up. |
| Imperative | …wake him up. |
| Modal Auxiliary | …you can wake him up. |
| finished action | Present Perfect | If he has moved into his new flat, … | Future I | …we will visit him. |
| Imperative | …visit him. |
| Modal Auxiliary | …we can visit him. |
| improbable action | should + Infinitive | If she should win this race, … | Future I | …I will congratulate her. |
| Imperative | …congratulate her. |
| Modal Auxiliary | …we can congratulate her. |
| present facts | Simple Present | If he gets what he wants, … | Simple Present | …he is very nice. |
Conditional Sentences Type II (unlikely)
| Condition refers to: | IF Clause | Main Clause |
| present / future event | Simple Past | If I had a lot of money, … | Conditional I | …I would travel around the world. |
| consequence in the past | Simple Past | If I knew him, … | Conditional II | …I would have said hello. |
Conditional Sentences Type II (impossible)
| Condition refers to: | IF Clause | Main Clause |
| present | Past Perfect | If I had known it, … | Conditional I | …I would not be here now. |
| past | Past Perfect | If he had learned for the test, … | Conditional II | …he would not have failed it. |
