when the job is left to himself, 跟when the job is left to him,有什么区别

Question

这句话的主句是he usually gets it done quickly.请问用himself跟用him句意上有什么区别呢？

Answer 1

从代词类型上说,him是宾格,“他”.himself是反身代词“他自己”(总的来说就是句意上的差别)

Answer 2

原句应该是：Left to himself, he usually gets job done quickly.
leave sb. to oneself 是短语，意思是“独自留下某人”，上句中过去分词短语作状语，相当于省略了He is，即，If he is left to himself, he usually gets it done quickly. 让他一个人呆着的时候，他通常很快就完成了工作.。
另外，我觉得只有when the job is left to him, 不存在when the job is left to himself的表达。