1 parent--perents
2 ...
3 keeps--goes to
4 ...
5 去掉to
6 去掉to
7 ...
8 去掉food
9 want--wants
10 去掉to
11 ...
12 ...
13 went--go
14 ...
15 to swim--swimming
16 mother's--mothers'
17 eat--have
18 去掉to
19 去掉to
20 may--can
21 swim --swimming
22 to work--working