`1.` We have studied English for five years.
`2.` I have worked for the company for a year.
`3.` She has worked as a nurse for 5 years.
`*` Công thức cách chuyển của các câu trên :
S + began/started + Ving/ TO V + thời gian trong quá khứ
= S + have/has + VPII + for/since thời gian