加入与介质结合力不强的元素铝，有阻碍介质渗入和扩散的作用。

We add the Al element to prevent medium's infiltration and diffusion.

youdao

没有什么是完美无缺的——着火了，有阻碍，有这样或那样的因素，一些东西就这样遗失了。

Nothing is perfect - there's fire, there's reluctance, there's this and that, things get lost.

youdao

其实，即使当你骑车时不打算使用GPS，手机或音乐播放器，另外一个良好的使用是简单易分离，哪怕是有阻碍的事件。

Actually, even if you don't plan to use a GPS, phone or music player while you ride, another good use is simply as an easily detachable, weather-resistant case.

youdao

And what are some of the obstacles to sustain high growth? Some questions are... we are going to look at today.

又有哪些因素可能阻碍其经济的,高速增长？今天我们会。,讨论相关的问题。

普林斯顿公开课 - 国际座谈会课程节选