Conditionals are a grammatical mood (remember moods) to express:
might have happened
would have happened
In other words, they talk about the consequences of facts/hypothetical situations.
Example: If you read this article, your writing may improve.
In this example the improvement of your writing may happen, doesn’t just happen. It is a possible consequence of the condition of reading this article. Your writing may improve if you read this article. And yes, the sentence still means the same when you turn it around, but like always, you use a comma when you put the ‘if’ part before the main clause.
Conditional sentences have two parts:
- The main clause, stating what could/would/should happen (in past, present, or future)
- The conditional clause (the ‘if’ clause), stating what the condition is for the main clause to happen
Conditional tenses can be positive, mostly using ‘if’ in the condition, or negative, using ‘unless’ in the condition. The negative conditional tenses use the same sentence structure as the positive conditional tenses.
There are four types of conditional sentences, expressing different meanings.
Zero Conditional Tense
This is a commonly used form of the conditional tense.
For general truths/realistic expectations, not specific situations.
If clause –> simple present
Main clause –> simple present
Example: If you write, you are a writer.
First Conditional Tense
These refer to possible conditions and probable real-world results in the future, based on facts. They are often warnings.
If clause –> simple present
Main clause –> simple future (may contain modals)
Example: If you write today, you will finish your book tomorrow.
Example: If you don’t write today, you may not finish your book tomorrow.
The second example includes a modal in the main clause.
Note: For the next two Conditional tenses, you need to know:
The present conditional tense is formed by two elements: would + infinitive
Example: It would work.
The perfect conditional tense is formed by the elements: would have + past participle
Example: It would have worked.
Second Conditional Tense
To describe a situation anytime that is very likely unreal. The if clause is hypothetical and/or completely unrealistic, i.e. not based on facts. The main clause, i.e. the result of the conditional, is probable but not certain.
Usually, a modal auxiliary verb (must, shall, will, should, would, can could, may, and might) is used in the main clause to express the (un)likelihood of the result happening.
If clause –> simple past
Main clause –> present conditional/present continuous conditional
Example: If I won the lottery, I would share it with you.
Often, If I was… is replaced by If I were…
Example: If I were you, I wouldn’t do it.
Again, modals are usually used in the main clause.
Example: He might write a review if you paid him for it.
Third Conditional Tense
To describe how things would be different if something had changed in the past. The main clause describes a contrast of the current reality, but the if clause could have been real.
If clause –> past perfect
Main clause –> perfect conditional/perfect continuous conditional
Example: If only I had paid more attention at school, I would be a better writer now.
Mixed Conditional Tense
The ‘mixed’ refers to the different times of the two parts of the conditional sentence.
- When you express a present result of a past condition
Both parts of the sentence are a contrast of reality.
- If clause –> past perfect
- Main clause –> present conditional
Example: If I sold a million books for 99c, I would be rich.
This is not the same as the Third Conditional Tense, where you use the past perfect and perfect conditional.
- When you express a past result of a present/continuing condition.
- If clause –> simple past (now or always)
- Main clause –> perfect conditional (before now)
Example: If I wasn’t so distracted by social media, I would have finished my novel a long time ago.
|Conditional sentence type||Usage||If clause verb tense||Main clause verb tense|
|Zero||General truths||Simple present||Simple present|
|Type 1||A possible condition and its probable result||Simple present||Simple future|
|Type 2||A hypothetical condition and its probable result||Simple past||Present conditional or Present continuous conditional|
|Type 3||An unreal past condition and its probable result in the past||Past perfect||Perfect conditional|
|Mixed type||An unreal past condition and its probable result in the present
An unreal (current) condition and its probable result in the past
(Table adapted from https://www.ef.co.uk/english-resources/english-grammar/conditional/)