1 can
2 could
3 can
4 have to
5 be able to
6 Should
7 ought
8 have to
9 must
10 may
11 might
12 can
13 May
14 can't
15 should
16 Could
1 can
2 could
3 can
4 have to
5 be able to
6 Should
7 ought
8 have to
9 must
10 may
11 might
12 can
13 May
14 can't
15 should
16 Could