He often (go)…………….. to school on foot

1.      He often (go)…………….. to school on foot.
2.      He often ( not go)…………….. to school on foot.
3.      He often (go)…………….. to school on foot ?
4.      Bad students  ( not work) ………………………hard.
5.      Good  students  ( work) ………………………hard.
6.      Good  students  ( work) ………………………hard?