Привет! Давай разберемся с предложениями. Вот правильные варианты:
- Have you seen Mary?
- I bought this mobile phone a week ago.
- Claire and Sarah have never been to Australia.
- Tim has worked as an architect for three years.
- We have visited this museum a million times!
- I took my dog to the vet last Saturday.
- Jake and Tom have been to the cinema. They'll be back in about an hour.
- It's been really cold since yesterday.
Если что-то непонятно, спрашивай!