If-clauses

If-clauses are used to talk about conditions. Note that an if-clause is an example of a subordinate adverb clause. Sentences containing an if-clause are sometimes called conditional sentences.

There are mainly four types of conditional sentences in English.

• Zero conditional
• First conditional
• Second conditional
• Third conditional

The zero conditional is used to talk about conditions that are always true. In this case, we use a simple present tense in the if-clause and the result clause.

• If I need help, I call her.

Conditional sentences are very common in English and therefore you should know how to use them correctly. In this lesson we will take a look at the most common conditional forms.

First conditional

Incorrect: If it rains we would cancel the match.

Correct: If it rains we will cancel the match.

Incorrect: If you hit the dog, it would bite you.

Correct: If you hit the dog, it will bite you.

Incorrect: If you invite her, she would come.

Correct: If you invite her, she will come.

Incorrect: If you ask more politely, she would help.

Correct: If you ask more politely, she will help.

When the verb in the if-clause is in the simple present tense, we use will/shall/can/may + infinitive in the main clause.

Second conditional

Incorrect: If you studied hard, you will get a first class.

Correct: If you studied hard, you would get a first class.

Incorrect: If she spoke English, she will get a good job.

Correct: If she spoke English, she would get a good job.

Incorrect: If I knew the answer, I would have told you.

Correct: If I knew the answer, I would tell you.

When the verb in the if-clause is in the simple past tense, we use would/should/could/might + infinitive in the main clause. Sentences of these types are used to talk about purely imaginary situations.

Third conditional

Incorrect: If you had studied hard, you would get a first class.

Correct: If you had studied hard, you would have got a first class.

Incorrect: If you had invited her, she would come.

Correct: If you had invited her, she would have come.

When the verb in the main clause is in the past perfect tense, we use would/should/could/might + have + infinitive in the main clause.