The Verb “To Be”: If A Sentence Is Conditional…

We recently looked at different forms of the verb “to be” and how to use them in a sentence. Once you have a good understanding of the usual ways we use those verbs, you will be ready to learn about the more complicated ways that “to be” is used in conditional sentences.

What is a conditional sentence?

A conditional sentence is sometimes called a conditional mood. We use it when we are writing/talking about something that only happens or exists under certain conditions.

In most conditional sentences, you will see an “if” clause. This tells us what has to happen/exist in order for something else to happen. The “something else” is in the main clause of the sentence. (Don’t worry too much about this right now—we’ll look at some examples in a few minutes.)

There are four types of conditional sentences. In each one, the verb form is a little different, which changes the meaning.

Note that if a sentence starts with an “if” clause, we add a comma before we start writing the main clause. (If you want to see an example, the sentence you just read starts with an “if” clause!)

Now, let’s move on to the four different types of conditional sentences.

Zero conditional

In a zero conditional sentence, whatever happens in the “if” clause always brings about the result in the main clause. This is something that happens over and over again. It does not refer to a specific incident.

If + simple present, simple present

(If something is x, then y happens.)

Both the “if” clause and the main clause in a zero conditional sentence are written in the simple present tense. In the example sentences below, the “if” clause is a simple present tense form of the verb “to be”. (If you need to review the different forms of “to be”, click here.) The second clause is a simple present tense form of a different verb. Both verbs are in boldface so you can find them more easily.

If I am late for work, the boss takes money out of my paycheck.

If the baby is hungry, he cries.

If the temperature is below zero degrees Celsius, water freezes.

If people are drunk, they are not fit to drive. (This sentence shows how you can use the verb “to be” in both clauses.)

First Conditional

A first conditional sentence begins in the same way as a zero conditional sentence, with an “if” clause written in the simple present tense. However, the main clause is a little different. We use the simple future tense with “will” followed by the infinitive (or root) form of the verb.

If + simple present, simple future

(If something is x, then y will happen.)

We use the first conditional when the situation in the “if” clause is likely—but not 100 percent certain—to bring about the outcome in the main clause. While a zero conditional sentence is used for a general truth or something that happens over and over again, the first conditional often refers to a specific incident or situation.

If John is sick, he will stay home from work.

If the meeting is postponed, I will work on the tax documents.

If we are at home tomorrow night, we will watch reruns of M*A*S*H.

If Carlos and Sammy are at the party, they will play their guitars.

Second Conditional

In a second conditional sentence, the situation in the “if” clause is imaginary, hypothetical, or unlikely to happen. The main clause reveals the outcome of this unlikely situation.

The second conditional is where things get tricky when we are using the verb “to be”. Regardless of the subject (I, you, he/she/it, we, they), when we write the “if” clause, we only use “were”, not “was”.

The main clause usually includes “would” followed by the infinitive, or root, form of a verb. Occasionally, you might see “could” in a second conditional sentence. You can also write a second conditional sentence with “might” or “should”, but these forms are rare.

If + simple past, would + infinitive

(If something were x, then y would happen.)

If I were a pirate, I would bury my treasure near these rocks.

If our boss were a woman, she would give more opportunities to female employees.

If they were generous, we would ask them to donate to the scholarship fund.

If I were a mom, I would teach my kids how to speak both English and Mandarin.

If I were a billionaire, you could design my mansion for me. (This is an example of how to use “could” in second conditional sentence.)

Third conditional

The “if” clause of a third conditional sentence centers around a past event that was likely, but which never happened. We use the “had been” form of the verb “to be” here.

Then in the main clause, we explain how circumstances would be different if the past event had occurred. We use “would have” followed by the past participle form of a verb. We can also use “could have” or (less frequently) “might have” or “should have”.

If + past perfect, would have + past participle

(If something had been x, y would have happened.)

If Rika had been at work yesterday, she would have finished the slides for the presentation.

If I had been at the scene of the accident, I would have called the police.

If Chris and Tammy had been at the family reunion, they would have seen the new baby.

If you had been in town last week, you could have helped me move the furniture. (Here is an example with “could” instead of “would”.)

If Pablo had been available, he might have gone to the conference. (Here is an example using “might”.)

Can you write a conditional sentence without using the verb “to be”?

Yes, you can write all kinds of conditional sentences without using “to be”. We focused on “to be” in this article because it tends to be the most confusing verb for non-native English speakers. However, to show you how conditional sentences work without “to be”, here are some examples.

If you pour gasoline on a fire, it further ignites the flames. (Zero conditional)

If it snows tonight, the kids will build a snow fort in the backyard. (First conditional)

If I owned a yacht, I would sleep there every night. (Second conditional)

If I had gone to Paris, I would have visited the Louvre. (Third conditional)

In the real world, the sentences we write are sometimes more complicated or nuanced that the examples provided in this article. Thus, if you are struggling with conditional sentences, click the blue box below. One of our TextRanch editors can take a look at your writing and let you know if you are on the right track.