| A.may | B.could | C.must | D.should |
| A.Must | B.Need | C.Should | D.Could |
| A.Must | B.Should | C.Could | D.May |
| A.May | B.Must | C.Could | D.Should |
| A.should, could | B.should, must | C.could, shouldn’t | D.could, couldn’t |
| A.Can | B.Must | C.Need | D.Should |
| A.need | B.can | C.must | D.should |
| A.can | B.must | C.can’t |