Различия в грамматике между американским и британским вариантами английского языка по сравнению с лексикой и написанием не всегда строги. Последнее время происходит заметное влияние американского варианта на британский.
Нужно сказать, что и американцы, например, часто, не всегда употребляют простое прошедшее время (Present Indefinite) вместо настоящего совершенного (Present Perfect).
Итак:
Британский Американский
Have you a brother? Do you have a brother?
Have you ever seen it? Did you ever see it?
I have written this letter I wrote this letter
I haven’t seen her for two year I haven’t seen her in two years
He was taken to hospital He was taken to the hospital
She was there all the time She was there all of the time
Your dog is not so big as mine Your dog is not as big as mine
I wish I were a student I wish I was a student
I suggest (that) we should I suggest (that) we go there
go there