`4.` It has rained for half an hour.
`5.` They started living/to live here for five years.
`6.` We have studied English for five years.
* Cách chuyển của 3 câu trên :
S + started=began + Ving/TO V + thời gian
= S + have/has + VPII + since/for thời gian
`VD` : I started learning English 3 years ago.
`→` I have learnt English for three years.