1. Child – children
1.孩子

2. Man – men
2.男人

3. Datum – data
3.数据

4. Criterion – criteria
4.标准

5. Medium – media
5.媒质

6. Foot –feet
6.脚，英尺

7. Tooth – teeth
7.牙齿

8. Mouse – mice
8.老鼠

9. Sheep – sheep
9.羊

10. Crisis – crises
10.危机

11. Stimulus – stimuli
11.刺激

12. Thief – thieves
12.贼，小偷

13. Wolf – wolves
13.狼

14. Leaf – leaves
14.叶子

15. Person – people
15.人

16. Life – lives
16.生命

17. Goose – geese
17.鹅

18. Thesis - theses
18.主题

19. Potato – potatoes
19.土豆

20. Cactus – cacti
20.仙人掌