the boy are sweeting all over.they must have been working 这句话怎么翻译,为什么用完成进行时
问题描述：
the boy are sweeting all over.they must have been working 这句话怎么翻译,为什么用完成进行时
答
the boys are sweeting all over.they must have been working
男孩们全身上下都在出汗.他们一定一直在工作.
用完成进行时表示从过去的某个时间点开始到现在一直都在做某事