Introduction to Conditional Sentences

Conditional grammar is way we use to join two clauses together to form one sentence using the word IF. For example:

If I won the lottery, I would buy a big house.

Sometimes we use alternatives to IF, and we will cover these in a later lesson.

In this lesson, we will look at the four basic conditional forms: zero, first, second, and third conditional.

GENERAL FORM

Conditional sentences follow this basic form:

A complete conditional sentence has two parts: a condition clause and a result clause. The condition clause features the word IF (or an alternative in an advanced conditional), and happens before the result clause (in real life / on a timeline). The result clause tells us what happens after the condition clause happens.

Remember!
clause = SUBJECT + VERB (+ OBJECT)

Note that if the condition clause is written first in the sentence, we use a comma to separate the two clauses. When the result clause is written first, there is no comma.

Which clause do we put first?

That depends on your preference, but typically, we put the condition first when we want to emphasise the condition. Similarly, we put the result first when we want to emphasise the result.

ZERO CONDITIONAL

FORM

The most common ZERO CONDITIONAL uses a present simple in the condition and a present simple in the result, as in the example above.

ZERO CONDITIONAL:
IF + PRESENT TENSE, S + PRESENT TENSE

Other present tenses are also possible in the condition clause.

If I'm studying for a test, I don't listen to music. (if + present continuous, S + present simple)

If I have only slept for two hours, I am grumpy. (if + present perfect simple, S + present simple)

If I've been drinking, I don't drive. (if + present perfect continuous, S + present simple)

FUNCTION

We use the ZERO CONDITIONAL to talk about real conditions and real results. 'Real' means that the actions are realistic and possible in real life. Often we talk about 'general truths' or 'things that always happen', in the past, present and future. If the condition is met, the result always happens

If you leave hot food out, it gets cold.

This sentence shows a situation that is generally true. Assuming the context is a typical situation (i.e. the weather is not too hot or not too cold), hot food will always go cold after a period of time. ZERO CONDITIONAL is the best way to express this situation.

FIRST CONDITIONAL

FORM

The most common FIRST CONDITIONAL uses present simple in the condition, and will in the result.

FIRST CONDITIONAL:
IF + PRESENT TENSE, S + PRESENT MODAL/TENSE + INF

It is also possible to use other present tenses in the condition, and other present modal verbs in the result. For example:

If you haven't come to class, you might/may still pass the test. (if + present perfect, S + may/might + inf)

If you've been studying every day, you are going to pass the test. (if + present perfect continuous, S + be going to + inf)

If you are running late, you should tell me immediately. (if + present continuous, S + should + inf)

FUNCTION

We use the FIRST CONDITIONAL to talk about real conditions and real results. We often use it to talk about possible present/future conditions and results. If the condition is met, the result is likely to happen.

What does it mean when we change the various tenses and modal verbs?

In the condition clause, we use basic present tenses with their basic meanings (i.e. present simple for general truths and habits, present perfect for recently completed actions with a present result etc.).

In the result clause, we can use a variety of present modal verbs and tenses. This will change the meaning or likelihood (probability) of the result action. Here is a summary:

• will = 95-100% chance of the result happening

• may/might = 50-60% chance of the result happening

• can = ability / possibility / permission

• could = offer / suggestion

• should/must = recommendation / obligation

• imperative = command

• be going to = future intention or plan

• present continuous = future arrangement

If it's warm this weekend, I'm going to hit the beach. (be going to = future intention or plan)

If you are running late, you must tell me immediately. (must = obligation)

If I get a pay rise, I might buy a new camera. (might = possibility / 50-60% chance)

First conditional is extremely common because we can use it for a variety of other real world meanings. For example:

If you come to Argentina, you can come stay at my place. (can = offer)

If you eat too many of those, you'll get really sick. (will = warning)

We can also talk about threats and compromises using a modified version of a conditional. When we 'threaten someone' we use an imperative instead of 'IF + SUBJECT', and use a conjunction like AND (in positive sentences) or OR (in negative sentences) between the condition and result clause. When we 'compromise' we use a normal clause (subject + verb) in the condition clause. For example:

Come inside and the dog will hurt you! Don't come inside or the dog will hurt you! (= threat / If you come inside, the dog will hurt you!)

You do the cooking and I'll do the washing up. (= compromise / If you do the cooking, I'll do the washing up.)

ZERO vs FIRST CONDITIONAL

The difference between ZERO and FIRST CONDITIONAL can be confusing. The table below will highlight the differences between similar sentences.

ZERO CONDITIONAL	FIRST CONDITIONAL
If the bus doesn't arrive, I am late for work. General situation Generally, on the days the bus doesn't arrive, I am late for work.	If the bus doesn't arrive, I will be late for work. Specific situation I am waiting for a specific bus now. If it doesn't arrive, I will be late today.
When the bus arrives, I smile at the bus driver. WHEN = IF	When the bus arrives, I will smile at the bus driver. WHEN is stronger than IF I am certain the bus will arrive.

SECOND CONDITIONAL

FORM

The most common SECOND CONDITIONAL uses past simple in the condition, and would in the result.

SECOND CONDITIONAL:
IF + PAST SIMPLE, S + PAST MODAL + INF

It is possible to use past continuous (for actions in progress) in the condition and other past modal verbs in the result. For example:

If you weren't talking so loudly, I could concentrate. (if + past continuous, S + could + inf)

If you paid attention, you might understand what I'm saying. (if + past simple, S + might + inf)

If I was you, I would wait before making a decision. (if + past simple, S + would + inf)

In the last example above, it is possible to use WERE instead of WAS in the condition. This is an acceptable exception to standard grammar rules (i.e. I was, NOT I were). In the second conditional, we can use the subjects I/he/she/it with both was/were - but only in the condition clause. You will find many native speakers using WERE as it is easier to pronounce. For example:

If I was/were you, I would wait before making a decision.

If she was/were running late, she would let us know immediately.

If it was/were socially acceptable, people would burp aloud more.

FUNCTION

We use the SECOND CONDITIONAL to talk about an unreal condition and unreal result. 'Unreal' means that the actions are imaginary, hypothetical and unlikely - in other words, a very small chance of them happening. It is important to remember that SECOND CONDITIONAL takes place in the present and future (not the past). If the unlikely condition is met, the result is likely to happen.

In the result clause, we can use a variety of past modal verbs to mean different things.

• would = 90-100% chance of the result happening

• might = 50-60% chance of the result happening

• could = ability (would be able to) / possibility / permission

If I won the lottery, I would buy a big house on the beach. (would = 90-100% chance of the result happening)

If she got the job, she might move closer to the city. (might = 50-60% chance of the result happening)

If they moved to Australia, they could learn how to surf. (could = possibility / ability)

It's very important to remember that the condition in each of these sentences is very unlikely (i.e. 1-20% chance of happening) and takes place in the present/future.

FIRST vs SECOND CONDITIONAL

The difference between using FIRST and SECOND CONDITIONAL is often subjective and depends on the speaker's circumstances. In other words, some things are more realistic for some people, and unrealistic for others.

FIRST CONDITIONAL	SECOND CONDITIONAL
If you pay attention, you will do well in the test. Possible / likely condition I believe you CAN pay attention; you just have to do it.	If you paid attention, you would do well in the test. Imaginary / unlikely condition I've never seen you pay attention, so I don't believe it's possible.
If she gets the job, it will be a huge boost to her career. Possible / likely condition I believe she has a good chance of getting the job.	If she got the job, it would be a huge boost to her career. Imaginary / unlikely condition I really don't think she will get the job; she's just not good enough.

THIRD CONDITIONAL

FORM

In the THIRD CONDITIONAL, we use past perfect simple/continuous in the condition, and would + have + past participle in the result.

THIRD CONDITIONAL:
IF + PAST PERFECT, S + PAST MODAL + HAVE + PP

Remember we use past perfect simple for shorter actions or state verbs, and past perfect continuous for longer actions (see Past Perfect and Narrative Tenses for a recap). Similar to SECOND CONDITIONAL, we can use other past modal verbs in the result clause.

If you had paid attention in class, you might have passed the test. (if + past perfect simple, S + might + have + pp)

If you hadn't been wearing your seatbelt, you could have died in the accident. (if + past perfect continuous, S + could + have + pp)

FUNCTION

We use the THIRD CONDITIONAL to talk about an unreal condition and unreal result. These are imaginary situations taking place in the past. If the imaginary condition had been met, the result would have happened.

In the result clause, we can use other past modal verbs to create different meanings.

• would = 90-100% chance of the result happening

• might = 50-60% chance of the result happening

• could = ability (would be able to) / possibility / permission

If you had paid attention in class, you might have passed the test. (might = 50-60% chance of the result happening)

If you hadn't been wearing your seatbelt, you could have died in the accident. (could = possibility / would have been able to)

SUMMARY

Conditional Sentences contains a lot of information, so it can be easy to make a mistake in conversation or even an English exam. However, if you categorise the information into groups (i.e. type, time, probability etc.), it can make your life a little easier. Here is a summary of all the information we have learnt today.

TYPE	TIME	% of HAPPENING	EXAMPLE
ZERO	All-Time: Past, Present and Future	REAL 100%	If you heat ice, it melts. If + present tense, S + present tense
FIRST	Present - Future	REAL >50%	If it is sunny, I will go to the beach. If + present tense, S + present modal/tense
SECOND	Present - Future	1-20%	If I won the lottery, I would buy a house. If + past simple, S + past modal
THIRD	Past	0%	If I had left at 7, I would have arrived on time. If + past perfect, S + past modal + have + pp

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