怎么样理解for now that

韦氏高阶词典sake有如此一个例句：Let'sassume, for argument's sake, that it was a mistake. = Let's assume, for thesake of argument, that it was a mistake. [=let's say for now that it was amistake so that we can see how that will affect our discussion]为了便于讨论，大家假设这是不对的。

后面这个：let's say for nowthat it was a mistake so that we can see how that will affect our discussion，不太了解，能否从结构上剖析一下这个句子，

let's say含义是“倘若”，fornow that不太了解为何这么用。

for now是状语，暂且，暂时。that从句是say的宾语从句。你把for now that 连在一块，是误读。