All of us use conditional sentences frequently in daily life. Here's one:
If you don't read this article, you'll have no understanding of conditional sentences!
Conditional sentences in English grammar
Conditional sentences are sentences that express the degree of probability that something will, might, or could happen/ have happened. Complete conditional sentences consist of two clauses; the conditional clause (sometimes called the if clause) and the consequence clause (sometimes called the main clause).
Conditional sentences examples
Here are some examples of different conditional sentences:
- If we lived in Spain, we could sunbathe all day long.
- When water reaches 100°C, it boils.
- If Jane doesn't eat, she will go hungry.
- If you want to go out tonight, you must clean your room.
- When John drinks, he vomits.
You can see that each sentence has three parts - the conditional clause (e.g. If we lived in Spain), the consequence clause (e.g. we could sunbathe all day long), and the conditional conjunction (the joining word, e.g. If).
Fig 1. A conditional sentence
We can also reverse the order of a conditional sentence so that the consequence comes first.
For example:
- Will you be ready if I swing by at 7 pm?
- Are you going to be upset if Michael leaves early?
- Mum says she won't be coming if Dad is there.
The biggest indicator that a sentence is a conditional sentence is that it contains the word If. The conditional clause is often referred to as the if-clause for this reason. However, conditional sentences don't have to contain the word if, and there are other coordinating conjunctions that can join the two clauses, such as when, unless, and as long as.
Types of conditional sentences in English
In English, there are five types of conditional sentences: zero conditional, first conditional, second conditional, third conditional, and mixed conditional.
These different sentence types reflect the level of probability that an event or situation will occur or could have occurred.
Zero conditional sentences
Zero conditional sentences are used to discuss truths. This can range from scientific facts to general truths. In these sentences, the conditional in question is either 100% likely or extremely likely.
We use conditional sentences to discuss habits, scientific facts, rules, and general truths.
- When you eat, your body digests your food.
- If you don't shower, you smell.
- If you don't drink, you get dehydrated.
- When I'm tired, I go to sleep.
The conditional conjunctions if and when are used interchangeably because it is certain that the consequence will occur.
When forming zero conditional sentences, the conditional clause and the consequence clause are always in the simple present tense. E.g. 'If ice gets hot, it melts' and not 'If ice gets hot, it will melt'.
| Conditional clause = Simple present tense | Consequence clause = Simple present tense |
| If I don't sleep | I'm cranky |
First conditional sentences
The first conditional is used to discuss a probable occurrence and its possible consequence. It's used to discuss situations that are realistic and occurring in the present and into the future.
We often use the first conditional to make promises, predictions, and threats.
- If I go to sleep now, I will be well-rested for tomorrow.
- If John starts working from next week, he'll have lots of money by next year.
- Mary will need a bigger bag if she plans to take all that food home.
- If you do not comply, I will have no choice but to proceed with the charges.
Here, the conditional clause remains in the simple present tense, but the consequence clause is in the future tense.
| Conditional clause = Simple present tense | Consequence clause = future tense |
| If I eat too much sugar | I will get cavities |
Second conditional sentences
The second conditional is used for unreal, improbable, or hypothetical events/situations, such as winning the lottery or meeting an A-list celebrity at the corner shop. Second conditionals can be used to discuss any time as they aren't based on real-life situations.
- If you met Justin Bieber at his concert, I would die!
- She would be shocked if I won the Olympics.
- If I had a billion pounds, I would buy a small island.
- If I were her, I would never speak to him again.
The conditional clause is in the simple past tense, and the consequence clause is in the present conditional - this means using a modal auxiliary verb (e.g. would, could, might) alongside the main verb.
| Conditional clause = Simple past tense | Consequence clause = present conditional tense |
| If I had a million pounds | I could buy a horse |
Fig 2. What would you do with a million pounds?
Second conditionals and the subjunctive mood
It is important to note that we use the subjunctive mood in second conditional sentences. This means we use the subjunctive form of the verb 'to be', which is 'were'.
Have a look at these examples:
If I were you, I wouldn't care.
If you were me, what would you have done?
If she were in a movie, she would be the main character.
If he were a billionaire, you would never need to work again.
If we were born in a different country, life might be different.
If they were us, they might understand our predicament.
Notice the use of 'were' after each pronoun rather than 'was' - this is the correct use of the subjunctive mood. The following sentence, 'If I was you, I wouldn't care.' is grammatically incorrect.
Third conditional sentences
Third conditional sentences are used when the event has passed and, therefore, the consequence can no longer occur.
We usually use the third conditional to reflect on the past, discuss events contrary to reality, and express regrets.
- If you had told me you needed it, I would have brought the charger.
- Mary would have reconsidered if John had not lied about the circumstances.
- If she had arrived five minutes earlier, she would have seen the entire exchange.
- If I had known you wanted to come, I would have invited you.
The conditional clause is now in the past perfect tense (e.g. had told), and the consequence clause is in the perfect conditional tense. This means the second clause contains a modal verb + have + a past participle verb (e.g. would have invited).
| Conditional clause = Past perfect tense | Consequence clause = Perfect conditional tense |
| If you had told me you liked the cake | I wouldn't have eaten it all |
Mixed conditional sentences
There are instances where conditional sentences are mixed. For example:
If I had learned to speak French as a child, I would be a French speaker today.
This is different from a third conditional sentence because, although it has a conditional clause in the past perfect tense, the consequence clause is in the present conditional tense and not the past tense.
Conditional sentences and punctuation
The only punctuation you have to worry about in terms of conditional sentences is the comma. The general rules are;
Use a comma after the conditional clause when it comes first in the sentence, e.g. 'If I were rich, I wouldn't work'.
No comma is needed when the consequence clause comes first in the sentence, e.g. 'I wouldn't work if I were rich'.
Conditional Sentences - Key takeaways
- Conditional sentences are sentences that express the degree of probability that something will, might, or could happen/ have happened.
- Conditional sentences have three components - the conditional clause (a.k.a the if- clause), the consequence cause (a.k.a the main clause), and the conditional conjunction (e.g. if, when).
- In English, there are five types of conditional sentences - zero, first, second, third, and mixed conditional sentences.
- When the conditional clause comes first in a sentence, separate the two clauses with a comma.
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