you may

use roller-skates

under the table

you may not

speak German

in pyjama trousers

you should

play with toys

on Fridays

you should not

write with green pencils

in English lesson

you must

use bows and arrows

in the cafeteria

you need not/needn’t

wear pink leggings

without shoes on

you must not/mustn’t

eat apple pie

in summer/winter

...

eat other monsters

with your tail

shake hands

before lunch

clean the blackboard

with dirty hands

...

...