1.mirror可以名词动用，表示“反映，体现”，相当于reflect.

Its ascent has mirrored the decline of traditional television viewing: Americans between the ages of 12 and 24 watch half as much pay-TV today as they did in 2010.

另外，如果我们说one thing mirrors another，意思是这两件事情非常similar，就像镜子里照出来的一样，比如

In the meantime, a second generation of MOOC is trying to mirror courses offered at traditional universities.

MOOC指的是“慕课”，全称为"Massive Open Online Courses"(大规模在线开放课程)

目前一些大学里已经把慕课当选修课了。这句话是说：同时，第二代慕课在设法模仿传统大学提供的课程。

如何表示某事不太可能实现？

表示某事不太可能实现，我们首先想到的就是impossible这个单词，或者是 a remote prospect，

...be/seem/appear a long way off的意思是“...离的还很遥远”，也就是“不太现实”的意思。还可以说"a pipe dream"，a pipe dream是“白日梦”的意思，相当于daydream，我们常用have a pipe dream来比喻幻想。

AI's replacement of humans seems a long way off.

AI's replacement of humans is a pipe dream.

如果我们成功做成了某件事，我们可以说：sth is no longer a pipe dream. 比如：

Studying at Peking University is no longer a pipe dream for me.