EXCEPTIONS OF CONDITIONAL

So far you have only learned the basic rules for Conditional Sentences. It depends on the context, however, which tense to use. So sometimes it's possible for example that in an “If Clause Type 1” another tense than Simple Present is used, e.g. Present Progressive or Present Perfect.

Conditional Sentences Type 1 (likely)

Condition refers to:	If Clause		Main Clause
future action	Simple Present	If the book is interesting, …	Future I	…I will buy it.
action going on now	Present Progressive	If he is snoring, …	Future I	…I will wake him up.
finished action	Present Perfect	If he has moved into his new flat, …	Future I	…we will visit him.
improbable action	should + Infinitive	If she should win this race, …	Future I	…I will congratulate her.
present facts	Simple Present	If he gets what he wants, …	Simple Present	…he is very nice.

Conditional Sentences Type 2 (unlikely)

Condition refers to:	If Clause		Main Clause
present / future event	Simple Past	If I had a lot of money, …	Conditional 1	…I would travel around the world.
result in the past	Simple Past	If I knew him, …	Conditional 2	…I would have said hello.

Conditional Sentences Type 2 (impossible)

Condition refers to:	If Clause		Main Clause
present	Past Perfect	If I had known it, …	Conditional 1	…I would not be here now.
past	Past Perfect	If he had learned for the test, …	Conditional 2	…he would not have failed it.