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.: Its nearly two years since my brother went away.
[Từ khi anh tôi đi xa nay gần hai năm.]
=> I havent 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.
=> Its 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.