OG11-51的解释里说，in that has largely gone out of use, it is considered stilted and overly formal. It also uses two words when one would do. 根据这个解释，基本上只要答案里出现in that就可以排除了。

我起初跟你想得一样，我想应该是不同人出题不同的思路而已，没有定式而言，看看这道题，OG208

208. Teratomas are unusual forms of cancer because they are composed of tissues such as tooth and bone not
normally found in the organ in which the tumor appears.
(A) because they are composed of tissues such as tooth and bone
(B) because they are composed of tissues like tooth and bone that are
(C) because they are composed of tissues, like tooth and bone, tissues
(D) in that their composition, tissues such as tooth and bone, is
(E) in that they are composed of tissues such as tooth and bone, tissues

正确答案选E,原因有3：

1.凡是举例不用like,用such as，排除B,C

2.不能用分词结构或者that引导的从句修饰tissue，尤其是that从句必须紧跟限定词，连逗号都不要加，排除A,B

3.可以考虑用which来进行修饰，因为which可以在不引起歧义的情况下进行跳跃修饰。但是同位语显得更为精确，因为指出了修饰的对象。

在上述理由中，并不需要区别 in that和because, 事实上估计也很难区别。在我看来，表达强因果用because可能更好一点，但是弱因果可能用for更顺畅一点，但是必须其他成分都一致合理的情况下。

应该可以这样说吧，如果两个选项一个用in that,一个用because，而两个选项都没有其他错误，那选用because。