Thì quá khứ đơn:
(+) My mother had dinner 2 hours ago.
(-) The student didn't study well enough to get good marks.
(?) Were you surprised at your best friend's ideas?
(+) They went to Nha Trang in their summer holiday.
(-) I wasn't happy with my final test result.
Thì hiện tại hoàn thành:
(+) My friends and I have watched this film since June.
(-) Jack hasn't finished his homework yet.
(?) Have you ever eaten seafood?
(+) I have learned/learnt English for 4 years.
(-) We haven't met each other since last Sunday.