Các bạn giúp mình giải bài này với 
----- Nội dung dịch tự động từ ảnh -----
1 I've sent all the letters this
morning.
I sent all the letters this-
morning.
2
3 She learnt to speak seven
languages.
4
5
6
7
8
She has learnt to speak seven
languages.
He worked for the company for
three years.
He has worked for the company
for three years.
He has sold a lot of cars today.
He sold a lot of cars today.
-a (It's four o'clock in the
afternoon.)
-b (It's eleven o'clock in the
morning.)
a (She is not still alive.)
(She is still alive.)
b
a (He still works there.)
(He doesn't work there
now.)
b
a
b
(It's 10 pm and he is not
working now.)
(It's 4 pm and he is still
working.)