改句子why not remember some new words every day?（why don"t

why not remember some new words every day?（why don"t…）
Why don't you remember some new words every day?（
let's do more sports.（is's a good idea…）
It's a good idea to do more sport.
tfy not to translate every word when you read English newspapers.（it's better not…）
It's better not to translate every word when you read English newspapers.
you should listen to English radio every day.（why not…）
Why not listen to English radio every day.
Don't play computer games too much.（shouldn't）
Shouldn't play computer game too much.