`20.` Does your mother often walk to marke?

Giải thích: often `=>` thì HTĐ

$\text{(?) Do/Does + S + V-bare + ...?}$

`21.` is/ are learning

Giải thích: now `=>` HTTD

$\text{(+) S + am/is/are + V-ing + ...}$

`22.` are you doing

Giải thích: now `=>` thì HTTD

$\text{(?) Am/Is/Are + S + V-ing + ...?}$

`23.` Does your mother walk

Giải thích: everyday `=>` HTĐ

$\text{(?) Do/Does + S + V-bare + ...?}$

`24.` don't play

Giải thích: in the morning `=>` thì HTĐ

$\text{(-) S + do/does + not + V-bare + ...}$

`25.` Is Hai working 

Giải thích: at the moment `=>` thì HTTD

$\text{(?) Am/Is/Are + S + V-ing + ...?}$

`26.` is doing 

Giải thích: now `=>` thì HTTD

$\text{(+) S + am/is/are + V-ing + ...}$

`27.` are playing/ play

Giải thích: at the moment `=>` thì HTTD

every afternoon `=>` thì HTĐ

$\text{(+) S + am/is/are + V-ing + ...}$

$\text{(+) S + V-s/es + ...}$

`28.` is the old man living

Giải thích: now `=>` thì HTTD

$\text{(?) Am/Is/Are + S + V-ing + ...?}$

`29.` teaches/ is teaching

Giải thích: often `=>` thì HTĐ

this morning `=>` thì HTTD

$\text{(+) S + am/is/are + V-ing + ...}$

$\text{(+) S + V-s/es + ...}$

`30.` is studying

Giải thích: now `=>` thì HTTD

$\text{(+) S + am/is/are + V-ing + ...}$

#chucbanhoctot

$#thaonguyeneakar$

`-` Thì HTĐ :

`+` KĐ : S + Vs / es `-` S + is / am / are + adj / n

`+` PĐ : S + don't / doesn't + V `-` S + isn't / 'm not / aren't + adj / n

`+` NV : Do / Does + S + V `?` `-` Is / Am / Are + S + adj / n `?`

`=>` `DHNB` : usually , always , often , ...

`-` Thì HTTD :

`+` KĐ : S + is / am / are + V-ing

`+` PĐ : S + isn't / 'm not / aren't + V-ing

`+` NV : Is / Am / Are + S + V-ing `?`

`=>` `DHNB` : now , at the moment , at present , ...

`20`.Does ... walk ?

`21`.is / are learning

`22`.are ... doing ?

`23`.Does ... walk ?

`24`.don't play

`25`.Is ... working ?

`26`.is doing

`27`.are playing / play

`28`.is ... living ?

`29`.teaches / is teaching

`30`.is studying

`\text{# TF}`