# data[].attributes.body
There are four types of conditional sentences.

It’s important to use the correct structure for each of these different types, because they express varying meanings.

Pay attention to verb tense when using different conditional modes.

Use a comma after the if-clause when the if-clause precedes the main clause.

# data[].attributes.body
Conditional sentences are statements discussing known factors or hypothetical situations and their consequences. We use them to communicate that something is true or happens only if something else is true or happens—that is, only under a certain condition. Complete conditional sentences contain a conditional clause (often referred to as the if-clause) and the consequence.

# data[].attributes.body
If a certain condition is true, then a particular result happens.

I would travel around the world if I won the lottery.

When water reaches 100 degrees, it boils.

# data[].attributes.body
Zero conditional sentences express general truths—situations in which one thing always causes another. When you use a zero conditional, you’re talking about a general truth rather than a specific instance of something.

# data[].attributes.body
If you don’t brush your teeth, you get cavities.

When people smoke cigarettes, their health suffers.

# data[].attributes.body
First conditional sentences are used to express situations in which the outcome is likely (but not guaranteed) to happen in the future.

# data[].attributes.body
If you rest, you will feel better.

If you set your mind to a goal, you’ll eventually achieve it.

# data[].attributes.body
Note that we use the simple present tense in the if-clause and the simple future tense in the main clause—the clause that expresses the likely outcome. This is how we indicate that under a certain condition (as expressed in the if-clause), a specific result will likely happen in the future.

# data[].attributes.body
Second conditional sentences are useful for expressing outcomes that are completely unrealistic or will not likely happen in the future. Consider the examples below:

# data[].attributes.body
Notice that the correct way to structure second conditional sentences is to use the simple past tense in the if-clause and a modal auxiliary verb (e.g., could, should, would, might) in the main clause (the one that expresses the unrealistic or unlikely outcome).

# data[].attributes.body
If I inherited a billion dollars, I would travel to the moon.

If I owned a zoo, I might let people interact with the animals more.

# data[].attributes.body
Third conditional sentences are used to explain that present circumstances would be different if something different had happened in the past.

# data[].attributes.body
If you had told me you needed a ride, I would have left earlier.

If I had cleaned the house, I could have gone to the movies.

# data[].attributes.body
Note that when using the third conditional, we use the past perfect (i.e., had + past participle) in the if-clause. The modal auxiliary (would, could, should, etc.) + have + past participle in the main clause expresses the theoretical situation that could have happened.