It's a good idea to study vocabulary every weekend.
You SHOULD study....
It's a good idea to help your parents around the house.
You SHOULD help ...
It isn't a good idea to listen to very loud music using headphones.
You SHOULDN'T listen to....
It isn't a good idea to be late to class on a weekly basis.
You SHOULDN'T be late ....
Do you want to get a good score in your next exam? Then, I think you .......... and ............
SHOULD / SHOULDN'T
It's necessary in our class to bring our books every day.
We HAVE TO / MUST bring ....
It's necessary to open the window between classes.
We HAVE TO / MUST open...
Is it really necessary to tidy my room just because aunt Deb is visiting?
DO I really HAVE TO tidy...? / MUST I really tidy....?
Is it a good idea to feed the monkeys next time I visit the zoo?
SHOULD I feed ....
Is it a good idea to go to a party without my parents' permission?
SHOULD I go....?
It's not necessary to carry an umbrella - it's going to be sunny today.
You DON'T HAVE TO carry...
It's not necessary for Sally to cook tonight, because her dad is making pancakes.
Sally DOESN'T HAVE TO cook ...
It's not necessary for mum to wake up early today - it's Sunday.
Mum DOESN'T HAVE TO wake up ...
