$6.$ We play badminton first. Next, we have some cool drink. 
$\rightarrow$ After having playing badminton, we have some cool drink.
$+)$ $After$ +$V_ing$ : sau khi làm một cái gì đó.
$7.$ Miss Mai went to the market. She bought some meat then.
$\rightarrow$ Before Miss Mai bought some meat, she had gone to the market.
$+)$ $Before$ + $S1$ + $V2/ed$ , $S2$ + $had$ + $Vpp$ : trước khi làm một cái gì đó......,....

$\text{MR.HBA}$

`6`. After playing badminton, we have some cool drink.

- After + Ving: sau khi làm gì đó

`7`. Before Miss Mai bought some meat, she had gone to the market.

- Before + S1 + V2/ed, S2 + had + Vpp: trước khi ...., ....