`1`. Thu has collected dolls since she was 10 years old.

`-`S + started/ began + to V/ V-ing + ... + when + S + V (quá khứ đơn) : bắt đầu làm gì khi ...

`=` S + have/has + Vpp + ... + since + S + V (quá khứ đơn): đã làm gì kể từ khi ...

`2`. We have worked in this museum since last year.

`-` S + started/ began + to V/ V-ing + ... + (pre) + time.

`=` S + have/has + Vpp + ... + since + time.

`-` since + mốc thời gian

`3`. Hung has done judo since 2020.

(Tương tự câu `2`)

`4`. They have built this bridge for six months.

`-` S + began/ started + to V/ V-ing + ... + time + ago.

`=` S + have/has + Vpp + ... + for + time.

`1` Thu has collected dolls since she was 10 years old

`2` We have worked in this museum since last year

`3` Hung has done judo since 2020

`4` They have built this bridge for six months

`@` Công thức áp dụng.

`-` S + started/began + to V/V-ing + ... 

`-` S + has/have + Ved/V3 + .... 

`-` for + khoảng thời gian 

`-` since + mốc thời gian

`@` Cách chia trợ động từ has/have.

`-` Chủ ngữ he/she/it đi với trợ động từ has

`-` Chủ ngữ I/we/you/they đi với trợ động từ have