$\text{ Why ? }$

→ Because they always pick up trash and protect the environment here.
→ Because they often go to work by bike and pick up trash to protect the environment.

why is the village always clean?

$\longrightarrow$ because they always take turns cleaning the neighborhood on occasions
$\longrightarrow$ because they do so for cleaner air
$\longrightarrow$ for helping them not to get sick from breathing dust

tạm dịch:

$\longrightarrow$ vì họ luôn thay nhau dọn dẹp khu phố vào các dịp
$\longrightarrow$ vì họ làm như vậy cho không khí trong sạch hơn
$\longrightarrow$ vì giúp họ không bị ốm vì hít thở bụi