We are going to study the conditional clauses which say what things can pass if a certain condition happens...
There are three types, the first is quite probable,
the second is hypothetical,
and the third is impossible.
All have two parts: MAIN CLAUSE IF CLAUSE or also
IF CLAUSE, MAIN CLAUSE.
Type 1
WILL IF PRESENT SIMPLE.
MAY/MIGHT (Possibility)
MAY/ CAN (Permission)
MUST/SHOULD (Command, request or advice)
PRESENT TENSE (Automatic or habitual results)
WILL IF PRESENT CONTINUOUS ( present action or future arrangement)
WILL IF PRESENT PERFECT
(finished action)
TYPE 2
WOULD+INFINITIVE IF PAST SIMPLE.
MIGHT/COULD+INF (certain result, ability or permission)
WOULD/MIGHT BE+GERUND
PAST SIMPLE IF PAST SIMPLE.
(automatic or habitual reactions in the past)
WOULD+INFINITIVE IF PAST CONTINOUS.
WIOULD+INFINITIVE IF PAST PERFECT.
TYPE 3
WOULD HAVE+PAST PARTICIPLE IF PAST PERFECT.
COULD/MIGHT HAVE+PAST PARTICIPLE
WOULD HAVE BEEN+GERUND
WOULD HAVE+PAST PARTICIPLE IF PAST PERFECT CONTINUOUS
We can omit if by putting had at the beginning, before the subject