Conditional Sentences – A Summary
Conditional sentences
Conditional sentences describe the result of something that might happen (in the present or future) or might have happened, but didn’t (in the past).
They are made using different English verb tenses with an ‘if clause’. The ‘if clause’ can go at the beginning or at the end of the conditional sentence.
There are four main types of conditional sentences.
| type | condition |
|---|---|
| Zero | condition always fulfilled |
| 1st | condition possible to fulfill |
| 2nd | condition in theory possible to fulfill |
| 3rd | condition not possible to fulfill (in the past) |
1. Form
| type | if-clause | main clause |
|---|---|---|
| Zero | Present Simple | Present Simple |
| 1st | Present Simple | will + infinitive |
| 2nd | Past Simple | would + infinitive * |
| 3rd | Past Perfect | would + have + past participle * |
2. Examples (if-clause at the beginning)
| type | if clause | main clause |
|---|---|---|
| Zero | If you heat ice, | it melts. |
| 1st | If I study, | I will pass the test. |
| 2nd | If I studied, | I would pass the test. |
| 3rd | If I had studied, | I would have passed the test. |
3. Examples (if-clause at the end)
| type | main clause | if-clause |
|---|---|---|
| Zero | It melts | If you heat ice. |
| 1st | I will pass the test | if I study. |
| 2nd | I would pass the test | if I studied. |
| 3rd | I would have passed the test | if I had studied. |
4. Examples (affirmative and negative sentences)
| type | Examples | ||
|---|---|---|---|
| long forms | short/contracted forms | ||
| 1st | + | If I study, I will pass the test. | If I study, I‘ll pass the test. |
| – | If I study, I will not fail the test. If I do not study, I will fail the test. |
If I study, I won’t fail the test. If I don’t study, I‘ll fail the test. |
|
| 2nd | + | If I studied, I would pass the test. | If I studied, I‘d pass the test. |
| – | If I studied, I would not fail the test. If I did not study, I would fail the test. |
If I studied, I wouldn’t fail the test. If I didn’t study, I‘d fail the test. |
|
| 3rd | + | If I had studied, I would have passed the test. | If I‘d studied, I‘d have passed the test. |
| – | If I had studied, I would not have failed the test. If I had not studied, I would have failed the test. |
If I‘d studied, I wouldn’t have failed the test. If I hadn’t studied, I‘d have failed the test. |
|
* We can substitute could or might for would (should, may or must are sometimes possible, too).
- I would pass the test.
- I can pass the test.
- I could pass the test.
- I might pass the test.
- I may pass the test.
- I should pass the test.
- I must pass the test.