Summary ''Conditional If''

                    Conditional If
 ‘’First Conditional’’
Nature: Open condition, what is said in the condition is possible.
Time: This condition refers either to present or to future time.

Formula:     ‘’ If + Present Tense(V1),  Will + infinitive / present tense / imperative’’
a. If you help me with the dishes, I will help you with your homework. (Will + Infinitive)
b. If the sum of the digits of a number is divisible by three, The number is divisible by three. (Will+ Present  tense)
c. If you see Mr.Fox tonight, tell him I am ill. (Will+ Imperative).

 ‘’Second conditional’’
Nature: unreal (impossible) or improbable situations.
Time: present; the TENSE is past, but we are talking about the present, now.

Formula:       ‘’If + Past Tense(V2),  Would + Infinitive’’
a. If I knew her name, I would tell you.(Would+ Infinitive)
b. Compare:  If I become president, I will change the social security system. (Said by a presidential candidate)
If I became president, I would change the social security system. (Said by a schoolboy: improbable)
c. Were replaces Was:
If I were a rich man... I would around the world.

 ‘’Third conditional’’
Nature: unreal.
Time: Past (so we are talking about a situation that was not so in the past.)
Formula :         ‘’If + Past Perfect Tense, Would have + Past participle (V3)’’
Example:
a. If you had warned me, I would not have told your father about that party.(But you didn't, and I have).
b. If I had had enough money, I would have gone to Japan.
‘’ I  do not normally use will or would in the conditional clause,
only in the main clause’’