Mr . Thao began teaching English in this shool 20 years ago. (for)

I started to learn French two years ago. (for)

My grandfather has grown a lot of beautiful trees in the garden.

It isn’t necessary for you to learn all the questions by heart.

-> You don’t

`=> Ans:`

`1`. Mr. Thao has taught English in this school for 20 years

`***` begin doing sth: bắt đầu làm gì

`=>` dùng thì HTHT

Thì hiện tại hoàn thành

(`+`) S + has/have + V-p 3

(`−`) S + has/have + not + V- 3

( `?` ) Has/have + S + V-p 3 ...?

`***` Dấu hiệu nhận biết: for, since, yet, already,...

`2`. I have learned French for two years

`***` start to do sth" bắt đầu làm gì

`=` S + have/has + PII

`3`.  A lot of beautiful trees have been grown in the garden by my grandfather.

`***` câu bị động thì HTHT

`***` S + has/have + PII

`=>` S + has/have been + PII

`4`. You don’t have to learn all the questions by heart.

`***` Isn't neccessary for sb to do sth

`=` don't have to: kh cần phải làm gì