i was quiet because that reason

错 :
i was quiet because that reason
这句比较CHINGLISH.

对 :
i was quiet for that reason
i was quiet because of that reason

第一句的"FOR"有"对於"的意思
第二句的"BECAUSE OF"则有"由於"的意思
文法上都没有错

不过用词上有点怪的地方，
或者可以把"QUIET"改成另一个词语
如果我没理解错误的话
可以把句子改成 :
I HAD NO IDEA FOR THAT REASON.

最后一个句子对，前两句中的because that ...和for that..后面要跟that引导

的从句，不能直接跟reason，第三个句子中的because of后接名词或短语，接

that reason 是对的。

i was quiet for that reason
i was quiet becasue of that reason
都对

i was quiet for that reason
i was quiet becasue of that reason
都对
because of由于；for the reason固定搭配，“由于那个原因”

第3 个
1.because 后面要是句子
2.quite不加for

第二句
because后不能直接加名词，because of应该在句首。