Missouri 的letter of intent 到底要写些什么啊

UMissouri 要一份personal statement 和一封letter of intent
这个letter of intent 到底是什么啊 。。。。。
问了小米但还是不太明白。。。。
A letter of intent is written in letter format addressed to the admissions committee. It sort of acts like a cover letter in a job application, as it explains why you're the best fit for our department and what your plans are and what you intend to do with your studies here. Whereas the personal statement is more of an essay explaining your background.
以上是小米的回复
但是还是没明白 background 又是什么啊
求申过的前辈们。。。。。