为什么这里用being 而不是is

Question

Anyone who has handled a fossilized bone knows that it is usually not exactly like its modern counterpart, the most obvious difference being that it is often much heavier.

Answer 1

这里的being 就是is 的非谓语

因为the most obvious difference being 这部分和前面是逗号相连，没有连词，必须规避is 这个动词，必须转换成非谓语

最显著的不同是。。。。。

Answer 2

being是动名词

’the most obvious difference being that it is often much heavier‘在整个句子中做状语，是独立主格结构，在这样的句型里动词一般用动词过去分词或动词现在分词形式。