`1.`It took him 2 hours to water the trees.
`→`He spent 2 hours watering the trees.
`⇒`Cấu trúc : It takes/ took (sb) + time + to V
`=`S + spend/ spends/ spent + time + Ving
`2.`They have learnt English from 4 years.
`→`They started learning English 4 years ago.
`⇒`Cấu trúc : S + have/has + VPII + since/for + time
`=`S + started + Ving + time + ago