conditionals
Conditional sentences are usually grouped into four main types.
1-the zero conditional is used to talk about common states or events(form=if/when+present simple + present simple).
If she knows you well,she is more talkative.
We say hello when we see each other in the street.
2-the first conditionals is used to talk about possible future states or events (form=if/when + present simple /continuous + will/be going to).
If you go away to study,you'll meet a Lot of people.
I'm going to start without him if he doesn't come soon.
3-the second conditional is used to talk about unlikely or imaginary states or events in the present or future( form= if + past simple /continuous + would/could/should/might).
If she spoke Spanish,she could apply for the job in Madrid.
They would leave their jobs and travel the world if they had the money.
With be , the second conditional uses were instead of was in formal context.
If I was/were good at languages , i'd learn Japanese.
4-the third conditional is used to talk about imaginary states or events in the past(form=if+ past participle + would/could/should/might+ have+ past participle).
If we have studied other cultures at school ,we might have been more confident about travelling.
If you had arrived in Japan three months ago,you would have seen
The cherry blossom.
*notice that when the if clause is the first in the sentence ,it is followed by a comma.There is no comma when the main clause come first
REFERENCE: Objective advanced