1.person是单数
people是复数
都是人的意思
2.特殊的：one-first two-second three-third 以及从21、22、23开始以后末位为123的数都这么变,比如21-twenty first 43-forty third,11、12、13按正常变,加th,如11-elventh
一般的：末尾加th,不过有些还需一点变形,如five-fifth twelve-twelfth
3.都可以
do exercise 锻炼；做练习
get lots of exercise 做大量锻炼
exercise more 多锻炼
exercise可数 不过do exercises比do exercise多一个意思：做操,一般做早操眼保健操之类都加s,表达做锻炼、练习之类两者都可以
4.是
5.Can you give me that cup?
Yes, I can.
No, I can't.
May I keep that cup?
Yes, you can.
No, you can't/mustn't.
Must I do this now?
Yes, you must.
No, you needn't/don't have to.
Need I work now?
Yes, you need.
No, you needn't/don't have to.
6.因为是‘反义’疑问句
They have been to Paris 2 times
→They have been to Paris 2 times,haven't they?