当你的面称赞你的人可能会在你的背后说你的坏话。

Those who praise you to your face are likely to speak ill of you behind your back.

youdao

是在你的背后也允许你获取尽可能多的空气，作为您所需要的。

Being on your back also allows you to get as much air as you need.

youdao

找把能靠背的椅子，椅背曲线要与自己的背部贴合，或者在你的背后卷条毛巾或放个枕头。

Choose a chair that supports your back, including the curve in your lower back (if not, place a rolled up towel or pillow behind your lower back for support).

youdao

The way he described is when you try to get down a quantum dimensions and you are standing there with your camera, just remember the sun is at your back and your shadow is always in the picture.

这种方法被他描述为,当你试着处理一个量子尺寸时,并且你试着拿着你的相机在那，记住太阳在你的背后,而你的影子总是在照片上。

麻省理工公开课 - 固态化学导论课程节选