• Used to report yes/no questions.

  Has the train arrived? I wonder if/whether the train has arrived. Would you like to know if/whether the train has arrived?

Difference

• Let me know whether she arrives.

  (No matter whether she arrives or not, let me know).

• Let me know if she arrives.

  (In case she arrives, let me know, if she doesn’t arrive, don’t let me know).

Examples

Would you like to know whether she’s free?

Are you coming to the cinema with us?

Did she join the meeting?

Please let me know if she is free.

I don’t know whether I can go. I have a lot work.

I’m not sure if she joined the meeting.

Let’s practice

• Is the soda free?

  I don’t know if/whether the soda is free.

• Would you like to learn French?

  I don’t think if/whether I would try, I would like it.

• Did he finish the project?

  I don’t know if/whether he finished the project.

• Does your friend like vegetables?

  I don’t know if/whether she likes vegetables.