Let's use buses instead of motorbike to avoid traffic jam.

`->`Why don't we use buses instead of motorbike to avoid traffic jam?

`-` Let's do sth.

`=` Why don't we  do sth?

Mary does not play tennis well

`->` Mary is not a good tennis player.

`1.` Why don't we use buses instead of motorbike to avoid traffic jam?

`-` Why don't we + V1

`@` Trans:  Tại sao chúng ta không sử dụng xe buýt thay cho xe máy để tránh ùn tắc giao thông?

`2.` Mary isn't good at play tennis

`-` S + be + good at + Noun/ Noun Phrase

`@` Trans:  Mary không giỏi về việc chơi quần vợt