when/if?

[cricks]

I'm thinking of going to see Tim. ..... I go, will you come with me?

Do you mind ..... I close the window?

John is still at school. ..... he leaves school, he wants to go to university.

Shall we have a picnic tomorrow ..... the weather is good?

I proszę o wyjaśnienie.

[milusiaa]

if-zdania warunkowe
when- zdania czasowe

Jeśli masz w daniu warunek - coś się wydarzy pod jakimś warunkiem - używasz if
Wobec tego we wszystkich zdaniach przytoczonych przez Ciebie użyłabym if z
wyjątkiem zdania:

John is still at school. When he leaves school, he wants to go to university.

Zastanawiam się czy if też by nie pasowało, bo przecież ten Janek się może nie
promować, aczkolwiek druga częśc zdania nie ma nic wspólnego z warunkiem, bo
to, że chcę coś zrobić nie ma nic wspólnego z tym, że jeszcze nie mam na to
szans;)
pozdrawiam

[kylie1]

John is still at school. WHEN he leaves school, he wants to go to university.

"If" does not fit in here. It means you are not sure if it happens or not. You
are questioning it. Most of us would think he WILL leave school sooner or
later.

[vm2301]

General rule says that IF is used when you're not sure whether sth is going to
happen or not, WHEN is used in the context of inevitability of it, it's just a
matter of time.
Both words, among others, are used in Conditionals.

If / when I have enough money I spend my holidays... (it sounds like having the
same meaning, doesn't it?
If I have enough money...... I will go... (maybe I'll spare enough)
When I have enough money ..... I will go...(I'm still saving money, I just need
more time to have the proper amount)

The difference could just lie in our attitude.

Of course there are sentences, in which it is LOGICAL to use only one of them
(see kylie1)as the other case may sound improbable or awkward.

My answer cannot be fully satisfying - no place for rewriting grammar books to
present all the possible cases.
What's more, I feel like having been asked about most typical cases from a
coursebook.

bye :)