Welcome to the forum, RALAIARINORO.
The title of your thread would have been better as Difference between American and British English. American English is one variety of English; British English is another.
Speakers of both varieties of English frequently use 'get' in place of more specific verbs, sometimes in in similar way, sometimes not. If you have learnt Britsh English, then American usage will sometimes seem strange to you. British usage can seem strange to those who have learnt American Englishit was a long time that I studied
Do you mean "It was a long time ago that I studied English" or "I have been studying English for a long time"?
But there are many things that I can't manage, for example, when I should use "get" in all its meanings. Why do
aAmericans get used touse it rather than bBritish tends to use"have". Is there a different meaning?