三、
1、tall,tall,shorter,shortest
2、the most friendly
3、the longest,longer
4、the most important
5、more carefully
6、more,more difficult
四、
1、How are your Chinese lessons going?
2、it's difficult to learn Chinese than English
3、Chinese grammar is a little easier.
4、it's faster for people to learn English than Chinese
5、Your English is better than my Chinese.