You can't park here.
You should check your emails before you send them.
I must finish this before I go home. You have to show your passport at the border.
You mustn't be rude to the customers. Don't spend more than the budget.
We don't have to work overtime.
You can use my office if you want.
We shouldn't increase our prices.
Good idea to
Not a good idea to
Necessary/very important to
Not possible to
Not necessary to
Possible to
Important not to