Conditional Sentences

1. What is a Conditional Sentence?

A conditional sentence tells the “conditions” in which something happens. It shows a possible cause and effect situation in the form of an “if…then” statement—in fact, every conditional sentence has a clause beginning with “if.” Conditional sentences let us express things that might or could have happened, could still happen, we wish could happen, or always happen in specific circumstances.


2. Examples

Conditional sentences are made of two clauses: one beginning with “if,” and one main clause. The order of the clauses can change. Here are some examples:

  • If you love me, let me go!
  • I wouldn’t be here if I had never met you.
  • If opportunity knocks, open the door.
  • You can’t be shy if you want to make friends.


3. Parts of Conditional Sentences

A conditional sentence has two clauses that really rely on each other to make sense—a conditional clause (which is a dependent clause) and a main clause (which is the independent clause). The tenses of these clauses determine the type of conditional sentence, which the next section will explain.

a. Conditional Clause

The conditional clause is a dependent clause beginning with “if.” All conditional sentences have a clause beginning with “if” because it expresses the conditions (what must or might have happen), like this:

  • If you want
  • If I am late to school
  • If you don’t do your homework
  • If I hadn’t eaten so much candy

Whenever a clause begins with “if,” it depends on more information to be complete—it must be paired with an independent clause. So, the dependent clause is only half of a conditional sentence, and couldn’t be a sentence on its own.

b. Main Clause

The main clause is what provides the rest of the information to complete a conditional sentence. It’s an independent clause that states the result of the conditional “if” clause. In other words, it’s the “then” part of an if/then situation. In these examples, the main clauses are orange.

  • If you want, I can go with you to the store.
  • If I am late to school, I will get detention.
  • If I don’t do my homework, the teacher yells.
  • If I hadn’t eaten so much candy, I might be hungry.

As you can see, these main clauses express complete thoughts and can be sentences on their own. But, you can also see that we also need them to complete the thoughts of the dependent clauses!


4. Types of Conditional Sentences

As a rule, conditional sentences are categorized by whether their situations are “real” or “imagined.” However, there are many types and forms of conditional statements, and they can be quite complicated, varying depending on time, its likeliness of occurring, and other factors. This article will help you understand the basics, and teach you how to recognize a conditional sentence when you see one.

a. “Real” Conditionals (Zero Conditional)

Real conditionals (also called zero conditionals) are sentences expressing the real conditions for things that happen, not hypothetical things (see Imagined Conditionals). They share true statements about things that will happen or do happen in certain conditions or circumstances.

Zero conditional sentences can come in many forms. But since they are based in fact, they only share past and present situations, NOT possible future situations. So, we write them using a combination of past and present tenses.

Present Tense

In many zero conditional sentences, both clauses are in the present simple tense, like this:

  • If you are happy, I am happy.
  • If there is snow, we make snowmen.
  • He cleans if I cook.
  • f you don’t mind, I need a glass of water.

But we also write them using other present tenses, like this:

Present continuous + Present simple

  • If it is snowing, we don’t drive.
  • I eat at home if Jane is cooking dinner.

Present continuous + Present continuous

  • If he is staying, I am going.
  • If the plant is dying, you are not watering it.

All of these examples express that every time A happens, B happens or we do B.

Past Tense

Zero conditionals can also reflect situation that already happened, like this:

Past simple + Past simple

  • If it snowed, we never drove.
  • If we had chocolate chips, we made cookies.

Past simple + Past continuous

  • We always made snowmen if it was snowing.
  • If Jane was cooking, I ate at home.

b. “Imagined” Conditionals

We use imagined conditional sentences to talk about hypothetical or “imagined” conditions that are possible, likely, or even impossible. Based on the level of possibility, there are three conditionals: first, second, and third.

First Conditional

The first conditional shares the result of situation in the future that we think is pretty likely to happen. Its form uses a conditional clause in the present simple, and the main clause in the future tense. The main clause will use a modal, like would, should, could, will, may, might, or can. Here are some examples:

  • If I sleep now, I will be up all night.
  • If I do well on my SATs, I could go to Harvard.
  • If you take the highway, you might hit traffic.
  • If he likes cookies, you should bake some for him.

Of all the conditionals, the first conditional expresses things that are most possible or likely to happen. As we will explain, with the second and third conditionals, things become less likely or even completely imagined.

Second Conditional

The second conditional shows possible outcomes that could occur in the present or future, if specific conditions exist. To put it simply, second conditionals reflect ideas of “if you did this, this can happen.” BUT, the “did” hasn’t actually happened yet, it’s just possible.

The second conditional’s form uses a conditional clause in the past simple, and the main clause in the future tense, also using modals. Here are some examples:

  • If you slept until 3pm, you shouldn’t be tired.
  • If you did well on the SATs, you will get accepted.
  • If you wanted to avoid traffic, you could take the highway.
  • If he ate all the cookies, you would have to bake more.

On a special note, the English language lets us use the past tense to reflect hypothetical situations that aren’t based in reality. So, even though the second conditional uses the past tense in the conditional clause, it’s expressing what could happen “if,” not what did already happen. It still expresses the present and future because the ideas are only possibilities. It also helps us use more polite language like this:

  • If you wanted, I could help you study.
  • If you needed me to, I could pick up your dry cleaning.
  • If you wouldn’t mind, I could use some help.

Third Conditional

The third conditional lets us contemplate what could have happened if things went differently in the past. It lets us reflect upon things in the way of “if this had happened, this could have happened.”

Its form uses the past perfect for the conditional statement, and the conditional perfect tense (would have + verb) for the main clause (you can also use other modals instead of would). Here are some examples:

  • If you had gone to bed earlier, you would have been well rested.
  • If you had done well on the SATs, you would have been accepted.
  • If you had taken the highway, you could have avoided traffic.
  • If you had made more cookies, we might have had enough.

As you can see, these sentences only reflect what possibly could have happened—not what still can or might happen.

c. Other Forms

There are several other special forms of conditions, like mixed conditionals and conditional sentences using will or would.

Mixed Conditionals

Sometimes we can mix the tenses to express conditions. Mixed conditionals reflect things that did or did not happen in the past that are still relevant now and in the future. We form a mixed conditional with the past perfect tense in the conditional statement and using would in the main clause of the sentence. Here are some examples:

  • If I hadn’t slept, I would be very tired.
  • If I had made more cookies, he would be eating them.
  • If there had not been traffic, I would be on time.
  • If I had failed the SATs, I would not be at Harvard.

Conditionals Using Will or Would

In English, will and would can refer to either the present or the future. That’s because we use will and would to express willingness to do something. Here are some examples:

  • If you will cook, I will clean.
  • If he would pick up the cookies, that would be great.
  • If you would show me the way, I will be very grateful.
  • If you would just stop crying, I will try to help you.


5. How to Write a Conditional Sentence

In a way, conditional sentences are some of the easiest to write because they always include certain things—particularly a conditional clause beginning with “if.” We can use them for both real and imagined scenarios, and to express all kinds of possibilities and hypothetical situations. What’s more, conditional sentences let us do these things by mixing together the past, present and future tenses without many restrictions.

When you want to use conditional sentences, you can just stick by these guidelines:

1. You always need 2 clauses:

  • a conditional clause beginning with “if”
  • a main clause

2. Present pieces of information that rely on each other:

  • the goal is to show that if one thing happens, another thing will happen.

3. Choose your tenses based on 2 things:

  • whether the situation is “real” or “imagined”
  • if it reflects past, present or future possibilities

Finally, here’s a chart to help you see the differences between the conditionals. It’s a lot to remember!

Zero (True)First (Likely)Second (Less Likely)Third (Impossible)Mixed (Possible)Would/Will
If he makes cupcakes, we eat them.If he makes cupcakes, we will eat them.If he made cupcakes, we would eat them.If he had made cupcakes, we would have eaten themIf he had made cupcakes, we could be eating them.If he would make cookies, I will eat them.


Test your Knowledge

What are the two parts of a conditional sentence?





TRUE or FALSE: Zero conditionals are about real conditions for the way things happen.



Which conditional sentences are imagined conditionals?





TRUE or FALSE: You can never mix tenses in a conditional statement.



1 Comment

  1. Reply

    I think this is a very didactic explanation.

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