The present perfect (have done)

You can also use the present perfect (have done) after when/after/until/as soon as: - Can I borrow that book when you've finished with it? - Don't say anything while lan is here. Wait until he has gone. If you use the present perfect, one thing must be complete before the other (so the two things do not happen together): - When I've phoned Kate, we can have dinner. (= First I'll phone Kate and after that we can have dinner.) Do not use the present perfect if the two things happen together: - When I phone Kate, I'll ask her about the party. (not When I've phoned} It is often possible to use either the present simple or the present perfect: - I'll come as soon as I finish. or I'll come as soon as I've finished. - You'll feel better after you have something to eat. or You'll feel better after you've had something to eat. After if, we normally use the present simple (if I do/if I see etc.) for the future: - It's raining hard. We'll get wet if we go out. (not if we will go) - I'll be angry if it happens again. (not if it will happen)

When and if

We use when for things which are sure to happen: - I'm going out later. (for sure) When I go out, I'll get some bread. We use if (not when) for things that will possibly happen: - I might go out later. (it's possible) If I go out, I'll get some bread. - If it is raining this evening, I won't go out. (not When it is raining)

25. When I've done/When and if