Please let me know when you finish or finished?

Question

A or B and Why?

I don't know whether I shall use "finish" or "finished"?

A. Please let me know when you finish.

B. Please let me know when you finished.

Answer 1

Used on its own, as in your second sentence, Finished is simple past, which describes something that happened in the past. The person has not yet finished: it isn't in the past, so you cannot use the simple past to talk about it. The first sentence, which uses present simple, is the only correct option of these two.

Please let me know when you finish.

This does have an overtone that the person is supposed to let you know at the exact moment that they finish. In ordinary speech, present perfect is probably more widely used:

Please let me know when you have finished.

The present perfect is used to talk about something that was completed in the past and has a lasting effect to the present. It suggests that informing you can take place any time after the person has finished.

Answer 2

  finish -  finished  - have finished

1) my friend with me, we are in the kitchen cooking and I finished first, I told him: Please let me know when you finish I am in my room waiting for.

2) My friend with me we have plan to play different games him tennis, me football but in the same compound.

I tell him: Please let me know when you finished and found me in side the big hall near the basketball playground.

4) My friend with me, we had have an appointment somewhere at 3pm and he go to the market to buy trouser, he came late 3:45pm, I told him we can't go we are very late because I told you: Please let me know when you have finished to bay quickly.