Differenences between american and british english

In British English the present perfect is used to express an action that has occurred in the recent past that has an effect on the present moment. For example:

I've lost my key. Can you help me look for it?
In American English the following is also...

possible:
I lost my key. Can you help me look for it?
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There are two forms to express possession in English. Have or Have got

Do you have a car? American
Have you got a car? British
He hasn't got any friends. B
He doesn't have any friends. A
She has a beautiful new home. A
She's got a beautiful new home. B
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Mean: (American English - angry, bad humored, British English - not generous, tight fisted)
Rubber: (American English - condom, British English - tool used to erase pencil markings)
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Words ending in -or (American) -our (British) color, colour, humor, humour, flavor, flavour etc.
Words ending in -ize (American) -ise (British) recognize, recognise, patronize, patronise etc
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American English - on the weekend / British English - at the weekend
American English - on a team / English - in a team
American English - please write me soon / British English - please write to me soon
...
...
why are we different? it's confusing!!!

This doesn't only occur with the english language. Even France French is different from Canadian French, and West Germany has a differing dialect from East Germany.

The worst I've seen, though, is right here in Ontario, Canada. There is differing dialect between southern ontario and northern ontario which are only a couple of hours apart.

Example:
Northern Ontario: Are you going out with him?
Southern Ontario: Are you going with him?

The first time I heard the southern version, I replied "going where?" lol

Many of your American sentences are used in British English as well.
Do you have a car?
Have you got a car?
He hasn't got any friends.
He doesn't have any friends.
She has a beautiful new home.
She's got a beautiful new home. These are all correct in British English. The main difference is the spelling, as you say.
I think most of the differences arise because the two languages (or dialects seeing as they're the same language) seperated a few hundred years ago with the colonisaton of the Americas by the British, and they evolved separetely. Also, American English had more of an input from other languages.

well, the only thing I want to know is that which one's more accurate??

Neither... depends where you are... in america you'd use american english, in britain you'd use british english...

I think one of the reasons I'm such a rotten speller is because growing up on the Canadian boarder I saw both American and Canadian spelling.

For the longest time I couldn't figure out why "defense" and "defence" looked equally correct to me. Turns out the former is the American spelling while the later is the Canadian and I saw both growing up. I did pick up on "labor" vs. "labour" and "color" vs. "colour" early on but some of the more subtle spellings like "ise" vs. "ize" are still tough for me to keep straight.

When I took French in college I became fascinated in idoms. These are terms that have an understood meaning that is different from their literal meaning. In English if you drink too much you might awaken with a "hang over." What is hanging over? it only has meaning because everyone here knows the term. In French they would say you have a "gueule de boys" or mouth of wood literally.

I was puzzled by some Brits who would say, "like chalk and chocolate" for things that are together but nothing like each other. I guess this is an idiom in England but not in America. Sometimes I completely missed things like a Brit who used to say "ta" which I thought was short for "ta ta" or goodbye but it turns out it is a short way of saying "thanks."

well here's my problem, I'm in England, but my mum's American, so I get mixed up so much,and now that my mum became my best friend, I talk to her so much... and when you hear me talking... I mix American english with British... and my mum keeps telling me to choose one of them!! I can't do that!! to me, it's like... impossible???!!