You ... wear a helmet when you ride a bike.
can't
mustn't
must
We ... play basketball in the library.
can't
must
don't have to
We ... borrow a ball from the school gym if we need one.
musn't
can
have to
The school director ... attend every meeting; her assistant can do it for her.
can't
mustn't
doesn't have to
We ... arrive at school before 8:10 a.m.
have to
can't
can
The goalkeeper ... wear gloves.
doesn't have to
can
has to
You ... use your phone during an exam.
don't have to
mustn't
can
You ... bring your own breakfast; the school provides it.
can't
don't have to
have to