`1.` My friends have learnt English since `2019.`

`->` S + started + to V + in + time

`=` S + have/has + P2 + since + time

`2.` She hasn't met her parents for two years.

`->` The last time + S + Ved/V2 + was + time + ago

`=` S + have/has not + P2 + for + time

`3.` Learning new languages is one use of the internet.

`->` V-ing đứng đầu câu với chức năng chủ ngữ

`->` be one use of sth: là `1` tác dụng của cái gì

`4.` We have worked at this company for ten months.

`->` S + began + V-ing + time + ago

`=` S + have/has + P2 + for + time

`5.` Robots allow people to clean the house quickly.

`->` allow sb to do sth: cho phép ai làm gì

`6.` My friend came while I was listening to music.

`->` hành động đang xảy ra thì một hành động khác chen ngang `->` thì QKTD

S + Ved/V2 + while + S + was/were + V-ing

`7.` Computer is used to store information.

`->` Bị động thì HTĐ: S + am/is/are + P2 + (by O)