Overview: Conditionals 1, 2, 3

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)