注射用长春新碱:还有这几句，谢谢了

My mother's hometown in Lijiang, therefore I have very many relatives
in Lijiang. This is my cousin. I may send the email to you? I send
English to you, you send Chinese to me, I practice English, you
practice Chinese.

My mother's hometown in Lijiang, I have many relatives in Lijiang. This is my Cousin Cousin. I can email you? I email you in English, you mail me in Chinese,and you practise English and I practise Chinese

My mother's hometown is Lijiang,so i have lots of relations in Lijiang.This is my brother.Could I write E-mails to you ?Mine is in English,and yours is in Chinese.I can practise my English and you can practise your Chinese.

My mother's hometown is Lijiang, so I have many relatives in Lijiang. This is my cousin. Could I write an e-mail to you? I'd like to write emails in English and I want you to write emails in Chinese. I can practise English in this way, and you can practise Chinse.

给楼上挑挑错.bryant126的回答中,
①My mother's hometown in Lijiang中缺少 is 这个系动词,My mother's hometown is in Lijiang或者说My mother's hometown is Lijiang都可以.
②I may send the email to you? 疑问句不用倒装,明显的错误.
③ I send English to you, you send Chinese to me有错.发送的是中文和英文的信件,而不是中文和英文这两种语言.

xiebing0714的回答很标准,可惜cousin重复了.而且,一楼的错误继续重演,I can email you?依然犯了疑问句没有倒装的错误.

soooooot的回答中某些词语不够准确.表哥是cousin而不是brother,亲戚是relative而不是relation.

呵呵,谢谢楼下的挑错.我的挑错确实不大厚道,不过被挑错的有一位是我朋友,所以口气有点不客气.您的挑错的确很准确,我深感佩服.您翻译的也确实比我的好得多.不管怎么说,我心中的确满怀敬佩.同时也向楼上三位道歉.

楼上的挑错不太厚道吧，那我也帮你挑挑错吧。就“I write an e-mail to you”译文原意显然是指长保持联系而不是简单地写一封信。所以该用write emails with you。 后句中“I want you to write emails in Chinese”显然欠妥有命令要求的意思。给出我的译文：
My mother's hometown is Lijiang, so I have lots of relatives there, and this is my elder cousin. Can I write e-mails with you? Maybe I can write mine in english while yours in Chinese, so by this way no only can I practise my English but also you can practise your Chinese.