They were all looking away — away from each other, away from the other students, away from anything in particular as far as I could tell.

【翻译】他们都把目光移开了——从彼此身上移开了，从其他学生身上移开了，从我所能说出的任何特别的地方移开了。

as far as，本质上是一个“原级比较”，现在已经演变成为一个固定词组，当作介词或连词使用。本义是“跟......一样远”，此外，还表示情况达到某种程度，意为“远到...程度；就…而言；在…范围内”，后面的几种意思都是由本义引申出来的。例如：

As far as I can tell, she's enjoying the course. 

据我判断，她喜欢这门课程。

For as far as I can tell, the first sharpener originated in 1900. 

据我所知，削铅笔机起源于1900年。

As far as I can tell,the house isn't worth the price they are asking. 

就我所能告诉你的来说，这房子不值他们的要价。

As far as I know, he will be away for three months. 

据我所知（就像跟我知道的范围一样），他将离开三个月。

As far as I can see, the whole matter is open-and-shut. 

依我看，整个事件是一清二楚的。

As far as we can make out, the damage is due to improper packing. 

根据我们弄清的真相，货损是因包装不善而造成的。

As far as I am concerned, I'm not against your plan. 

就我而言，我并不反对你的计划。

The land west of the mountains stretches as far as the eye can see. 

群山以西的地域宽得一望无际。

As far as I can see, you've done nothing wrong.

据我所知，你没做错什么。