[解析]
Dear Tom,
Thanks for your last letter.It's great that you want to improve your Chinese.I'd be happy to give you some advice.(表明书信目的)
The best thing you can do is to start a course in Chinese.There are lots of schools in Canada which offer lessons by qualified teachers.【高分句型一】Try to make friends with a native Chinese speaker and practise what you learn in class with him/her.【高分句型二】It would also be a good idea to read Chinese magazines or books,and watch films and TV programs in Chinese,as this would give you a lot of useful practice.Naturally,from now on I expect you to write to me in Chinese as much as you can.(介绍学习汉语的方法)
If you follow my advice,I'm sure your Chinese will improve gradually.Good luck!(表达祝愿)
Best wishes,
Li Hua