1. It is not a pen/ It is a pen ?

2. Nam and Ba are fine/ Are Nam and Ba fine ?

3. They are not twenty/ Are they twenty ?

4. I'm not Thu/ Are you Thu ?

5. We are not eighteen/ Are you eighteen ?

6. She is not Lan/ Is she Lan ?

`-` Thì HTĐ ( ĐT Tobe ) :

`+` KĐ : S + is / am / are + adj / n

`*` I `-` am

`*` He , She , It `-` is

`*` You , We , They `-` are

`+` PĐ : S + isn't / 'm not / aren't + adj / n

`*` I `-` am not

`*` He , She , It `-` isn't

`*` You , We , They `-` aren't

`+` NV : Is / Am / Are + S + adj / n `?`

`*` Am `-` you , we , they 

`*` Is `-` he , she , it

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

`1`.

`( - )` It isn't a pen

`( ? )` Is it a pen ?

`2`.

`( - )` Nam and Ba aren't fine

`( ? )` Are Nam and Ba fine ?

`3`.

`( - )` They aren't twenty

`( ? )` Are they twenty ?

`4`.

`( - )` I'm not Thu

`( ? )` Are you Thu ?

`5`.

`( - )` We aren't eighteen

`( ? )` Are you eighteen ?

`6`.

`( - )` She isn't Lan

`( ? )` Is she Lan ?

`\text{# TF}`