A Review of Conditionals and Conditional Sentences

Conditionals sentences are an integral part of the English language. They are used every day in many situations; from the bank to driving to giving directions, they can be found just about anywhere. Let’s go through a review of conditional sentences.

Basics of Conditional Sentences

While conditional sentences come in many forms, shapes and sizes, there are really two common characteristics that unite them into this broad category known as the ‘conditionals’.

1. A conditional sentence (or at least the part that forms the conditional) has two clauses.

Conditional sentences are, as it states in the name, conditional, meaning that one clause is dependent on another in some way, shape or form. This is the ‘condition’ clause or the clause that holds the situation that needs to be fulfilled before the action or situation in the other clause becomes relevant. Here is an example:

If she goes home, I will go home too.

The first clause (‘if she goes home’) is the condition that needs to be met. The second clause (‘I will go home’) is the result that will occur if the condition is fulfilled (the eponymous ‘she’ going home).

2. The clauses are joined by a conjunction that shows a relationship or dependency               between the clauses

For those who are unfamiliar with the term, a conjunction is a word used to connect clauses or sentences together. The most well-known clause is ‘and’. Specifically with conditional clauses, conjunctions that show a relationship between the two clauses in the sentences is needed. This is usually fulfilled by the word ‘if’, but other conjunctions can also fill this function and change the clause relationship. Such words include: when, unless and while.

This review is going to cover five kinds of conditionals: zero, first, second, third and mixed. Some argue that there are only four kinds of conditionals and that ‘mixed’ conditionals should not be considered a separate type of conditional. I would disagree as a mixed conditional has a different function than the other four. If this sounds confusing, don’t worry. We will get to them soon =)

Conditional Tense (and its aspects)

In order to talk about conditional sentences, we first need to mention the conditional aspects that we need to use when creating these sentences. If you are unfamiliar with what tenses and aspects are or what the tenses are in English, you might want to read this review first.

In total, there are four conditional aspects: simple conditional, perfect conditional, continuous conditional and perfect continuous conditional. If you haven’t noticed, these follow the same pattern for aspects of other tenses (e.g. present). In fact, the conditional aspects follow the future aspects very closely.

Simple conditional

A simple conditional is the most common type of aspect in the conditional tense. The simple conditional is similar to the future simple. It uses ‘will’ plus the main verb in the bare infinitive. For the simple conditional, instead of using the verb ‘will’, it uses the verb ‘would’. Therefore, the structure is:

would + main verb in bare infinitive

Example: I would go …

Perfect Conditional

The perfect conditional also has similarities to the future perfect. The future perfect uses the verb ‘will’ followed by the auxiliary (helping) verb ‘to have’ in the bare infinitive followed by the main verb in the past participle (which defines the perfect tense). The perfect conditional follows the same pattern but uses the verb ‘would’ in place of ‘will’.

would + have + main verb in past participle

Example: I would have gone…

Continuous Conditional

The continuous aspect is the verb ‘to be’ and the main verb in the present participle case (verb + ‘ing’). The continuous conditional includes the verb ‘would’ in the front, forming:

would + be (conjugated) + main verb in present participle

Example: I would be going…

Perfect Continuous Conditional

Just as with the previous aspects, this one also follows the perfect continuous aspects of other tenses:

would + have + be (past participle) + main verb in present participle

Example: I would have been going…

Let’s look at the first type of conditionals:

Zero Conditionals

A zero conditional, also known as the zeroth (0th) conditional, is the simplest of all the conditional sentences. The zero conditional refers to a situation that is happening now or always happens. This situation is also real and possible. If the condition is fulfilled, the result is highly likely. In practical terms, this means that general truths use the zero conditional very often, such as the following:

If you heat ice, it melts.

Ice melts if you heat it.

The clause in blue is the condition clause. Note that it starts with the conjunction ‘if’. The clause in red is the result. The meaning of this sentence states that if thermal energy is applied to frozen water, it turns into its liquid state. This is a condition-result combination that is extremely likely to happen. It is also a general truth; in other words, that the time of the condition is irrelevant and the result will always be the same. The ice could be heated up yesterday, today, tomorrow or in 50 years by me, you or anyone else in the world; the result is constant.

The zero conditional is one of the easiest conditional sentences to learn because of its structure, which is shown below and colour coded to match the previous example. There are two possibilities:

Conjunction* + present simple tense, present simple tense.
Present simple tense + conjunction* + present simple tense.

If you need a review of tenses, you can find one here.

* It is important to note that while the conjunction is usually ‘if’ in conditional sentences, it can be any conjunction that shows a causal relationship between the condition and the result. Possible conjunctions include: after, as a consequence of, as a result of, as long as, as soon as, assuming, because, before, but for, even if, if, if only, once, only if, on the condition that, provided, providing, since, therefore, unless, until, when, whenever, wherever, whether, yet. Note you can only use some of these conjunctions in certain types of conditionals. This is because of the relationship that they establish between the clauses.

First Conditionals

A first conditional in English refers to a possible condition and its probable result. This situation is real and possible. The basic structure is as follows:

Conjunction* + present simple tense, future simple tense.
Future simple tense + conjunction* + present simple tense.

Example: If you build it, they will come.

As you can see, there are a few differences from the zeroth conditional. Firstly the first conditional uses the future simple tense to talk about the result rather than the present simple. This is because of how English talks about the future. When we use the present to talk about the future, we mean that it is extremely likely to happen (for example, we have planned something and it is happening soon, such as the following sentence: ‘I am going to the doctor tomorrow’). When we use the ‘will’ future, the outcome is less certain or farther in the future. For more about the different ways to talk about the future in English, click here.

Secondly the first conditional has a time relationship. We saw that the zeroth condition shows general conditions, meaning that the outcome of the condition was always the same. For the first conditional, the situation occurs in the present and causes a subsequent (following) result/reaction that happens in a point past the current point of speaking. This could be in either the near future or the far future.

Thirdly the zeroth conditional will happen no matter what but the first conditional only states the most probable result. Just because it is probable does not mean it is guaranteed to happen.

Zeroth conditional: If you heat ice, it melts.

Examples that follow the laws of physics are the easiest to show the use of the zeroth conditional. If the condition is fulfilled (thermal energy is added to frozen water) then the result will happen no matter what (assuming it heats the ice above the melting point).

First conditional: If it rains tomorrow, I will bring an umbrella.

Here, there is a possibility that the condition of water falling from the sky will happen tomorrow. If this happens, then there is the possibility that I will take an umbrella with me when I leave the house. This action is NOT guaranteed and so the result may not occur, even if the condition is fulfilled.

Second Conditionals

The second conditional shows a hypothetical (unreal) situation in the present and the probable result. Unlike the first conditional, this hypothetical situation is very unlikely to happen, which means that even though the result is probable if the situation occurred, it is still very unlikely. There are two basic structures for the second conditional, the most common of which is below:

Conjunction + past simple tense, simple conditional -OR- continuous conditional.
Simple conditional -OR- continuous conditional + conjunction + past simple tense.

Example: If this thing happened , this would be the result.

Example: If I had tonnes of money, I would be going on holiday all the time.

There is one very important exception to this construction: if you are using the verb ‘to be’, it is conjugated following the subjective mood. While this sounds complex, it just means that the conjugation is always ‘were’ (e.g. I were, you were, he/she/it were, we were, they were.

Example: If I were you, I would go see her.

This leads us quite nicely into the second structure. This other structure is not very common today. The structure is as follows:

If*+ ‘were to’ + verb in bare infinitive, simple conditional -OR- continuous conditional.
Simple conditional -OR- continuous conditional + if*+ ‘were to’ + verb in bare infinitive.

Example: If this thing were to happen, this would be the result.

Example: If I were to have tonnes of money, I would be going on holiday all the time.

There are a few additional restrictions to this form because it uses the English subjunctive mood. As a rule, you only use this construction with the conjunction ‘if’. Secondly, while this form does not generally have a difference in meaning from the first one, it is much more formal; it is much older than the more modern form (i.e. first construction). For those reasons, it is a dying form of the second conditional. In fact, in some English-speaking countries, you may rarely hear this construction although you may still see it in writing, especially for legal or governmental documents.

Third Conditionals

The third conditional shows hypothetical (unreal) situations in the past and their probable result. Because this situation has already past, it is now impossible that the result will actually occur. But how can we show the past if we used the simple past in the second conditional? Remember that English can talk about events further in the past using the past perfect (had + past participle), which is what happens in the third conditional:

Conjunction + past perfect, perfect conditional (would have …) –OR-or perfect continuous conditional (would have been …-ing)

Perfect conditional (would have …) –OR-or perfect continuous conditional (would have been …-ing) + conjunction + past perfect

Example: If it had rained, you would have had to use an umbrella.

Example: If it had rained that much, I would have been rowing to work for the past few days.

Overview of 0th, 1st, 2nd and 3rd conditionals

Before moving on to mixed conditionals, let’s look at the conditionals that we have covered so far by putting them on a timeline.


In this image, X marks the condition (the part with the conjunction in the sentence). This is the time that the condition is fulfilled. The line that comes afterwards is the possible time in which the result may occur. The zeroth conditional is red, the first conditional is green, the second conditional is blue and the third conditional is orange.

As we can see here, the condition for the 0th conditional (red) can happen at any time and the result occurs (usually) immediately or in the near future. Because the 0th conditional is used to describe general situations, these conditions can occur in the past, the present and the future and the condition can also occur in those time frames.

For the first conditional (green), the condition can happen now or in the near future since the simple present is used. The result can occur very soon after the condition is fulfilled or even far into the future. For example, ‘If she moves to Japan next year, I shall save enough money to visit her in 20 years’.

The second conditional (green) starts in the present (now) and describes an unreal situation (one which would not happen) and the outcome. This would create a kind of parallel universe where this situation happened instead of what we know to be a reality, which is why the line is drawn away from the timeline axis.

The third conditional (orange) also follows the same pattern as the second conditional but the condition starts in the past, causing a shift in when the result could occur.

Sometimes, the second and third conditionals can be confusing to keep straight. How do you know if something is a second or a third conditional just by looking at it? The big difference is this:

The second conditional uses ‘would’ but not ‘have’ as an auxiliary verb:

If I were you, I would review the topics outside of class as well.

If I were you, I would be skipping class at this very moment.

The third conditional has the verb ‘to have’ in both clauses:

If I had won the lottery, I would have travelled around the world.

If I had won the lottery, I would have been travelling around the world instead of teaching at Jena University.

You can also practice using the following table I prepared. Complete the sentence given using the correct conditional:

If I had to teach Spanish to a person who knew nothing about the languageIf someone pays me a compliment
If I had been born in the 17th centuryIf I had lived in another country when I was in high school
If I won a lot of moneyIf my car had been stolen yesterday
If I went out this weekendIf you had asked me for $100 last week
Most people would be a lot happier ifWere you to ask me to help you cheat on the next exam
If men had babies instead of womenIf I could change one thing about my life right now
If I could have any job in the worldIf I was born 10 years earlier
If I could meet someone famousIf my best friend got into a lot of trouble.

Mixed Conditionals

As the name suggests, a mixed conditional sentence uses parts from the normal conditionals above. The most common types of mixed conditionals are mixes of the second and third conditional, but why is this so? Well, if you try to mix parts of the zeroth and first conditionals, you just create the other conditional as their structures are very similar.

But why would anyone want to mix the second and third conditionals? What would be the point? If you look back at the previous conditionals, you notice that there is a condition that happens and then a result happens afterwards. This makes sense; this is how time as well as cause and effect work. But what about if something in the future caused you to do something different in the present? What if something happening now or that is generally true caused you to do something different in the past? What if we just need to shift the time but it is not covered under conditionals 0 through 4? That is where mixed conditionals come in.

Some generic examples of the two most common types of mixed conditionals:

If this thing had happened, that thing would happen. (had happened = 3rd conditional condition, would happen = 2nd conditional result)
If this happened, that thing would have happened. (happened = 2nd conditional condition, would have happened = 3rd conditional result)

This may sound counter-intuitive, so here are some examples that may help to clarify the point:

If I had studied, I would have my driving license. (had studied = 3rd, would have = 2nd)

If you had crashed the car, you might be in trouble. (had crashed = 3rd, might be = 2nd)

If we didn’t trust him, we would have sacked (US = fired) him months ago. (did = 2nd, would have sacked = 3rd)

If I wasn’t afraid of spiders, I would have picked it up. (wasn’t = 2nd, would have picked = 3rd)


Uses of the Conditionals

0: general truth if a condition is fulfilled (at the same time) – If you heat it, ice melts.

1: a possible (real) condition and its probable result (at the same time or soon in the future) – If it rains, I will take an umbrella.

2: a hypothetical condition and its probable result (at that same time/a consequence in the very near, hypothetical future) – If you went to bed earlier, you would wake up late.

3: an unreal past condition and its probable result (also in the past) – If it had rained, you would have got wet.

Mixed: Change of time (a condition in the past and result in the present, for example) – If I wasn’t in the middle of another meeting, I would have been happy to help you (unreal present and probable result in the past). I would be a millionaire now if I had taken that job (probable result in the present from unreal past).

Conditional Structures

Conditional TypeCondition clauseResult clause
Zeroth (0)If + present simplePresent simple
If you heat ice, …… it melts
First (1)If + present simpleFuture simple (will)
If you buy the tickets,…… I will go with you
Second (2)If + past simplePresent simple conditional (would + verb) OR present continuous conditional (would be + verb-ing)
 If + ‘were to’ + bare infinitive (older form)
If I were you,…… I wouldn’t be so hasty to dismiss his advice.
If I were to go, …I would need to be escorted
Third (3)If + past perfectPresent perfect conditional (would have + past participle) OR present perfect continuous conditional (would have been + verb-ing)
If I had gone to the store,… I would have bought pretzels.

Other modal verbs

There is one additional note about conditionals before we finish. While the modal verb usually used is ‘would’, other modal verbs can be used, including might and could:

I could be a millionaire now if I had invested in ABC Plumbing.
If I had learned to ski, I might be on the slopes right now.
If you did crash the car, you should be in trouble.

Want more English materials? Why not check out my Learning English page for more articles, such as French Phrases in English the French Wouldn’t Understand or about Puns.

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