`1` Are you doing yoga at the gym now ?

No , I am not

`-` Thì HTTD `-` DHNB : now

`-` do yoga : tập yoga

`-` at the gym : tại phòng gym

Cấu trúc thì HTTD

`(+)` S + am/is/are + V-ing

`(-)` S + am/is/are + not + V-ing

`( ? )` Am/is/are + S + V-ing ?

`2` Did you do any exercise yesterday ?

Yes , I did

`-` Thì QKĐ `-` DHNB : yesterday

Cấu trúc thì QKĐ

`(+)` S + V2/V-ed

`(-)` S + did + not + V-inf

`( + )` : Did + S + V-inf ?

`1`.Are you doing yoga at the gym now ? `-` No , I'm not

`\rightarrow` Thì HTTD ( NV ) : Is / Am / Are + S + V-ing ?

`\rightarrow` `DHNB` : now

`->` Reply : Yes , S + is / am / are `-` No , S + isn't / 'm not / aren't 

`2`.Did you do any excercise yesterday ?

`\rightarrow` Thì QKĐ ( NV ) : Did + S + V ?

`\rightarrow` `DHNB` : yesterday

`->` Reply : Yes , S + did `-` No , S + didn't

`\text{# TF}`