Grammar
Introduction
Conditionals: an introduction
What are conditionals in English grammar? Sometimes we call them 'if clauses'.
They 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.
There are four kinds:
-
The Zero Conditional
(if + present simple, ... present simple)
If you heat water to 100 degrees, it boils.
-
The First Conditional
(if + present simple, ... will + infinitive)
If it rains tomorrow, we'll go to the cinema.
-
The Second Conditional
(if + past simple, ... would + infinitive)
If I had a lot of money, I would travel around the world.
-
The Third Conditional
(if + past perfect, ... would + have + past participle)
If I had gone to bed early, I would have caught the train.
The zero conditional
We can form a zero conditional sentence with two present simple verbs (one in the 'if clause' and one in the 'main clause'):
if + present simple, ... present simple
This conditional is used when the result will always happen.
If water reaches 100 degrees, it always boils.
It's a fact.
The result of the 'if clause' is always the main clause.
The 'if' in this conditional can usually be replaced by 'when' without changing the meaning.
For example:
If water reaches 100 degrees, it boils.
(It is always true)
If I eat peanuts, I am sick.
(This is true only for me, maybe, not for everyone, but it's still true that I'm sick every time I eat peanuts)
Here are some more examples:
-
If people eat too much, they get fat.
-
If you touch a fire, you get burned.
-
People die if they don't eat.
-
You get water if you mix hydrogen and oxygen.
-
Snakes bite if they are scared.
-
If babies are hungry, they cry.
The first conditional
The first conditional has the present simple after 'if', then the future simple in the main clause:
if + present simple, ... will + infinitive
It's used to talk about things which might happen in the future.
Of course, we can't know what will happen in the future, but this describes possible things, which could easily come true.
-
If it rains, I won't go to the park.
-
If I study today, I'll go to the party tonight.
-
If I have enough money, I'll buy some new shoes.
-
She'll be late if the train is delayed.
-
She'll miss the bus if she doesn't leave soon.
-
If I see her, I'll tell her.
First vs. Zero Conditional
The first conditional describes a particular situation,
The zero conditional describes what happens in general.
Compare these two sentences:
If you sit in the sun, you get burned --> natural consequence of sunbathing (zero conditional)
If you sit in the sun, you'll get burned --> talking about today (first conditional)
The second conditional
The second conditional is formed by if + past simple, ...would + infinitive
To talk about things in the future that are probably not going to be true.
- If I won the lottery, I would buy a big house.(I probably won't win the lottery)
- If I met the Queen of England, I would say hello. ( It won't happen)
- She would travel all over the world if she were* rich. (But she isn't)
- She would pass the exam if she ever studied.(She never studies, so this won't happen)
Secondly, we can use it to talk about something in the present which is impossible, because it's not true.
- If I had his number, I would call him.
(I don't have his number now, so it's impossible for me to call him)
- If I were* you, I wouldn't go out with that man.
* We can use 'were' instead of 'was' with 'I' and 'he/she/it'. This is mostly done in formal writing.
How is this different from the first conditional?
This kind of conditional sentence is different from the first conditional because this is a lot more unlikely.
Second conditional: If I had enough money I would buy a house with twenty bedrooms and a swimming pool. (I'm probably not going to have this much money, it's just a dream, not very real)
First conditional: If I have enough money, I'll buy some new shoes.
(It's much more likely that I'll have enough money to buy some shoes.
Another example:
Second conditional: If she studied harder, she would pass the exam.
(I think that she won't study harder, or it's very unlikely, and so she won't pass).
First conditional: If she studies harder, she'll pass the exam.
(I think it's possible she will study harder and so she'll pass)
The third conditional
The Third Conditional is formed by if + past perfect, ...would + have + past participle
It talks about the past. It's used to describe a situation that didn't happen, and to imagine the result of this situation.
- If she had studied, she would have passed the exam. (but, really we know she didn't study and so she didn't pass)
- If I hadn't eaten so much, I wouldn't have felt sick. (but I did eat a lot, and so I did feel sick)
- If we had taken a taxi, we wouldn't have missed the show. (but we didn't take a taxi and so we missed the show)
- She wouldn't have been tired if she had gone to bed earlier. (but she did not go to bed earlier and so she was tired)
- She would have become a teacher if she had gone to university. (but she did not go to university and so she did not become a teacher)
