Could you find some examples about violating the honor code in your school? I know some from the undergraduate students I TAed before. I think that you could tell her about these kind of true things. Hopefully she could understand that cheating is a serious issue here.

直接告诉她这个事情如果败露是比较严重的，然后再告诉她给她也不能给一样的，都是改过的，或者就说早就修了，都弄丢了。不要死要面子活受罪啦，多痛苦～～，虽然我自己有时候也是这样～～
我的一个女同学她就是这样，她把自己的旧作业给了一个学弟，那个教授太牛了，居然记得她的作业，发EMAIL问她，把她吓坏了，求了几次才放过了她，后来给了那个男生一个C

if I were you,
just tell her directly
if she can not understand you
and push you away
then she is not worth being your friend

I have met this situation before
and I did the opposite
I gave all my homework to her
I don't think she still remember this thing
I feel very bad
Will NOT do that even one more time!!!

绝对不能给她抄的，不然一起受处分哦。告诉她，这里的老师对作业都有记录的。

我姐以前有一个同学，也是个中国女孩，常去她房间玩，偷偷的抄了她作业，结果被老师发现了。幸好我姐平时表现好，那老师还挺喜欢她的，就没有处分她，但还是对她说了事情的严重性。那个女孩当然逃脱不了乐。

you must say no to her. Honor code is serious.

if she's new in America, it's better to tell her a white lie than explain why you don't want to give her the old coursework and exams...

I think it's all right to tell her you lost all your materials when moving.

thanks all for your kindly reponse. I decide to tell her directly that I can't lend her the homeworks but I 'll be happy to answers any questions she may have.
She has been in US for over 3 years, I guess she'll understand the consequence.

That's a really good way~:)

support you!!!

哎,就告诉她老师警告过的,你不想惹麻烦.她能理解你,就不会生你的气以后还有的朋友做.反之,你也没有必要在乎她.