同学你好，该知识点来自沪江网校《【Uni智能】雅思7分名师VIP签约-高中起点【挑战奖励班】》的课程，想要更系统的学习，欢迎进入课程学习。不仅可以和更多的同学一起学习，而且还有老师、助教随时的学习指导和知识点解答哦。

同学你好。

这是个虚拟条件句。条件句部分省略了连词if，采用了倒装语序，造成理解上的困难。正常语序是：
A skilled migrant may earn several multiples of what his income would have been if he had stayed at home.
或者：If he had stayed at home,a skilled migrant may earn several multiples of what his income would have been
然后再进一步理解主句结构：
multiple of表示“好几倍于”
what his income would have been（他本来可能达到的薪资水平）

may...would have done：
would+have+done”虚拟语气，表示对过去事情的假设，意思是“本来会做”。

1. I would have told you all about the boy's story, but you didn't ask me. 我本来会告诉你这个小男孩的故事，但是你没有问我。

2. Without your help, I wouldn't have achieved so much. 没有你的帮助，我是不会取得如此大的成绩。

希望有帮助到你~