In English, there are many ways to express situations according to a certain condition in the present and the past, as well as a varying degree of possibility. Basically, we have the following framework to express different situations:
Conditional 1:
a) possible event that depends on a condition
b) refers to the future
c) grammar tenses=present, future
If I
get into a car accident, my auto insurance
will cover the hospital bills.
(present) (future)
He
will call you if his plane
lands early.
(future) (present)
If the citizens
elect a new president, then I
will find a new job.
(present) (future)
I
will inform you if I
get the job.
(future) (present)
Conditional 2:
a) possible OR impossible situation
b) the possible situations refer to the future, the impossible is hypothetical (use your imagination!)
c) grammar tenses=past, "would" (a modal verb)
d) *Even though we use the past tense, it DOES NOT refer to the actual past
If I
won a million dollars, I
would donate to SOS charities. (possible in the future)
(past) (modal verb)
If I
were you, I
would see a doctor as soon as possible. (impossible, hypothetical)
(past) (modal verb)
I
would renovate the house if I
had more money. (possible in the future)
(modal verb) (past)
I
would be King John III if I
could be anybody for one day. (impossible, hypothetical)
(modal verb) (past)
Conditional 3:
a) impossible situations
b) impossible situations that refer to a finished, unreachable past
c) grammar: past perfect (had+past participle), modal perfect verb (would have+past participle)
If my mother
had spoken German with me as a little girl, I
would have been a fluent German speaker! (past perfect) (modal perfect verb)
She
would not have failed the exam if she
had studied more.
(modal perfect verb) (past perfect)
If I
had gone to the doctor a month ago, I
would have recovered by now.
(past perfect) ( modal perfect verb)
They
would not have broken up if he
had treated her better.
(modal verb) (past perfect)