There are a few grammatical differences between British and American English:
In American English the past simple is often used to give new information or to announce a recent happening:
– I lost my key. Can you help me look for it?
The past simple is used with just and already:
– I’m not hungry. I just had lunch.
– `Don’t forget to post the letter.’ `I already posted it.’
Americans use the past simple with yet:
– I didn’t tell them about the accident yet.
In American English the forms I have / I don’t have / do you have? are more usual than `I’ve got / I haven’t got / have you got?’:
– We have a new car.
– Do you have any change?
Americans often use the infinitive in structures with insist/suggest etc.:
– They insisted that we have dinner with them.
– Jim suggested that I buy a car.