樓上的12錯了.
1-one-first
2-two-second
3-three-third
4-four-forth
5-five-fifth
6-six-sixth
7-seven-senventh
8-eight-eighth
9-nine-ninth
10-ten-tenth
11-eleven-eleventh
12-twelve-twelfth
13-thirteen-thirteenth
14-fourteen-fourteenth
15-fifteen-fifteenth
16-sixteen-sixteenth
17-seventeen-seventeenth
18-eighteen-eighteenth
19-nineteen-nineteenth
20-twenty-twentieth
21--twenty-one--twenty-first