韦氏高阶词典sake有这样一个例句:Let's assume, for argument's sake, that it was a mistake. = Let's assume, for the sake of argument, that it was a mistake. [=let's say for now that it was a mistake so that we can see how that will affect our discussion]为了便于讨论,我们假设这是错误的。
后面这个:let's say for now that it was a mistake so that we can see how that will affect our discussion,不太明白,能否从结构上分析一下这个句子,
let's say含义是“假如”,for now that不太明白为什么这么用。