English Lessons and Exercises
Conditionals - Alternatives for "if"

How to use "only if" in English Grammar

'Only if' means 'only one condition happens". This form basically means the same as 'if'. The main emphasis is on the result.
  • You can go out only if you do your homework.
Here, there is just a condition of doing homework. Then, he can go out. If he doesn't do his homework, he cannot go out.


When 'only if' begins the sentence you need to invert the main clause.

  • Only if you study hard can you be successful. 

             (You can be successful only if you study hard)

  • Only if she promises me will I let her go home.

  • Only if we are members can we enter.

Example Sentences for "only if"

  • He's welcome to come along only if he behaves himself.

  • Only if you do well on your exams will we give you your bicycle.

  • I will let you go only if you tell the truth.

  • Tom could have started work again only if he had apologized to the manager.

  • Sharks are generally aggressive only if they are disturbed.

Don't confuse with "if only"

If only means I wish.
If only is totally different from only if.

  • If only I could pass the exam. = I wish I could pass the exam.

  • If only you had come earlier. = I wish you had come earlier.

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