What Is a Conditional Sentence?

A conditional sentence tells what would or might happen under certain conditions. It most often contains an adverb clause beginning with ‘if’ (expressing the condition in which the other clause would be true) and an independent clause usually including a modal verb like ‘will,’ ‘would,’ ‘could,’ or ‘might.’ 

Either clause can go first: if it’s cold, I’ll wear a jacket” or “I’ll (I will) wear a jacket if it’s cold.” “If Johnny had studied, he would have gotten a better grade” or “Johnny would have gotten a better grade if he’d studied.”  (See Complex Sentences for more on independent and dependent clauses.)  

Types of Conditional Sentences

a girl reading, imagining a castle, and thinking

There are four kinds of conditionals:

The zero conditional is present tense and expresses a fact. It tells about something that always happens under certain conditions.

  • If people get hot, they usually sweat, but if dogs get hot, they pant.
  • If plants don’t get any water, they die. (or: Plants die without water.)
  • When babies are hungry, they cry.

The 1st conditional tells what may happen in the future if a certain condition is met:

  • “If you study hard, you will be a success.” (or: “If you study hard, you might get into Harvard.” or: “If you study hard, you’re going to do well in school.”)

The 2nd conditional imagines what would happen if something were true-- but it’s not. This is often called the “present unreal conditional.” The verb after the ‘if’ is in simple past form, even though it’s talking about the present. This tells listeners that the suggestion is imaginary, not true.

(In formal use the verb ‘be’ is also in plural form, even for singulars, as another clue. See “if something were true” above. Speaking casually, many people use ‘was.’)

  • “If I were president, I would make some big changes.”
  • “What would you do if you had a million dollars?””Well, first I would pay off all our debts, and take my wife on a cruise. Then I would set up a trust fund for our grandchildren...”

The 3rd conditional talks about how the past might have been different if different steps had been taken. The verb after the ‘if’ is again farther into the past-- in this case, a past perfect, compared to a conditional perfect using would or another modal in the independent clause.

  • “If you had studied, you would have passed that exam.”
  • “If she hadn’t gotten sick, she might have won the singing contest.”
  • “If that car had been two seconds later, it would have hit you.”
  • “If I had known the trouble you were having, I would have been more gentle and more caring...” (from a poem.)
  •  “I would have listened to you if you had practiced what you preached.”

For a little more about how to use 'will,' would,' 'might,' 'could,' and other modal verbs that can help form conditional tenses, see Modal Verbs.

Home> English Verb Tenses> Conditional Sentences.

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