MODAL VERBS

Level 2: must, mustn´t

Level 2: should, shouldn´t
Level 2: can,can´t
Leval 2: can, must, should

Level 2: can, cannot, must, must not

Level 3: can, can´t, could. couldn´t

Level 3:can, could, may, must, mustn´t, should, shouldn´t, have to