I. LIÊN HỆ GIỮA SINGE, FOR và AGO - Thì Quá khứ đơn và Hiện tại hoàn thành đơn (Relation between Since, for and ago) - the Simple past and Simple present perfect tenses)
e.g.: It’s nearly two years since my brother went away.
(Từ khi anh tôi đi xa nay gần hai năm.)
=> I haven’t seen my brother for nearly two years.
=> I last met my brother nearly two years
=> The last time I met my broiher was nearly two years ago.
I haven't met my brother since the year 2000.
(Tôi không gặp anh tôi từ năm 2000.)
=>The last time I met my brother was the year 2000.
=> I last met my brother in the year 2000.
=> It’s over a year and a half since I last met my brother.
=> I haven't met my brother for over a year and a half.
=> I lasi met my brother over a year and a haft ago.