简言之in that 是从一个角度解释，because引导“全局解释”

Mayanist

仔细体会看Longman Dictionary Of Contemporary English的解释和例子就可以发现这个区别:

in that -- used after a statement to begin to
            explain in what way it is true

看上面的黑体字就理解in that 和because的两点区别：使用位置，和表达的含义。第一点简单，第二点看下面例子：

I've been lucky in that I have never had to worry about money.

我的翻译是：从不缺钱花（的角度），我很幸运。如果我们将 in that 改为because: I've been lucky because I have never had to worry about money. 我不缺钱，所以我很幸运。比较可以发现这两种说法表达的含义不一样，前者是从一个特定角度(in what way) 来解释
            I have been lucky is true；后一种说法暗示钱是be lucky的唯一（或者说全局）决定因素。

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相关短语：inasmuch as (formal) used to explain the way in which, what you are saying is true: Ann is guilty, inasmuch as she knew what the others were planning.

OG11黄皮书51题解释：In that is a conjunction
            that means inasmuch as; because in that has largely gone out of use, it is considered stilted and overly formal. It also uses two words when one would do. 似乎说 in that 不受欢迎了。但OG10-208 又选有in that的答案。说明要看具体场合，解释部分与结果的关系。

更多例子参见大牛们的讨论：http://forum.chasedream.com/dispbbs.asp?BoardID=23&replyID=95666&id=14357&skin=0

关于新东方的in that>because>because of >for优先说法就不必管它了。

songlovegt

Good job, thanks

wentaow2008

 great conclusion!

aeoluseros

agree.because is used to express a simple causal relationship whereas in that qualifies the previous statement.

iamyamy

easy to understand !

zbna5

UP UP!!!

Natalie蝶

精彩！！

StanMarsh

What about the use of for? In OG11-51, it uses for rather than in that. 

elaine1031

up

mikecello

fabulous explanation~~