But for now let's simply say that we have a diffraction which we know occurs only by wave-like behavior and it involves the use of x-rays. Why x-rays?

但现在让我们来简单假设一下,我们知道,只波才发生衍射,而且衍射涉及了X光的使用，为什么是X光？

麻省理工公开课 - 固态化学导论课程节选

I held off for a very long time, but I just got mine a month ago. And now I don't know how I live without it.

我拖了好长时间，一个月前才买的。而且现在我不知道离开它该如何生活。

没有智能手机活不了 - SpeakingMax英语口语达人