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.

CONDITIONALS

1) ZERO CONDITIONAL

We zero conditional to express general truths and facts (often things based on scientific fact) and we use with the simple present tense.

Formation

If + Present Tense,	Present Tense
If you heat water to 100ºC,	it boils.
Present Tense	if + Present Tense
Water boils	if you heat it to 100ºC.

Example:

- If you drop an apple, it falls. = An apple falls if you drop it. (This is an absolute truth based on scientific fact - gravity).

- If you don't do your homework, I am disappointed. = I am disappointed if you don't do your homework. (This is a general truth based on previous knowledge - you know that I am disappointed if people don't do their homework).

NOTE: Most zero conditional sentences mean the same thing if "when" is used instead of "if".

2) FIRST CONDITIONAL

We use first conditional to express situations based on fact in the present or future (things which may happen) and we use with the simple future tense with “will”.

Formation

If + Present Tense,	Future “will”
If I go there,	I will see our teacher.
Future “will”	if + Present Tense
I will see our teacher	if I go there.

NOTE:

- We never use will or won't in the “if clause”.

- We often use unless which means “if ... not”.

Example:

- If I have time today, I will phone my friend. = I will phone my friend if I have time today. (It is possible that I will have time – therefore the condition is real).

- If I go to England, I will buy some Cheddar cheese. = I will buy some Cheddar cheese if I go to England. (It is possible that I will go to England - therefore the condition is real).

3) SECOND CONDITIONAL

We use second conditional to express unreal situations in the present or future. It is often used to express a wish with the simple past tense and “would”.

Formation

If + Past Simple,	Past Future “would”
If I were you,	I would marry her.
Past Future “would”	if + Past Simple
I would marry her	if I were you.

NOTE: We never use would or wouldn't in the “if clause”.

Example:

- If I were you, I wouldn't do that. = I wouldn't do that if I were you. (I am not you - therefore the condition is unreal).

- If I had more time, I would do more on my websites. = I would do more on my websites if I had more time. (I don't have more time - therefore the condition is unreal).

4) THIRD CONDITIONAL

We use third conditional to express conditions in the past that did not happen. It is often used to express criticism or regret with would have, could have or should have and we use third conditional with the past perfect tense.

Formation

If + Past Perfect,	Past Future Perfect
If I had met her,	I would have told her about my heart.
If I had met her,	I could have told her about my heart.
If I had met her,	I should have told her about my heart.
Past Future Perfect	if + Past Perfect
I would have told her about my heart	if I had met her.
I could have told her about my heart	if I had met her.
I should have told her about my heart	if I had met her.

NOTE: We never use would have, or wouldn't have etc in the “if clause”.

Example:

- If I hadn't helped you, you would have failed. = You would have failed if I hadn't helped you. (I helped you so you didn't fail).

- If it had been sunny, we could have gone out. = We could have gone out if it had been sunny. (We didn't go out because it wasn't sunny).