look的用法：
用作不及物动词，意为“看，望，瞧”。
1、单独使用时，后不跟介词。如：
I looked but saw nothing.我看了，但什么也没看见。
Look！ Here comes the bus.瞧！汽车来了。
Look before you leap.三思而后行。
2、和at连用。如：
The teacher is looking seriously at us.老师正严肃地看着我们。
Look at these pictures. How beautiful they are！看这些画，它们是多么漂亮啊！
3、和其它某些介词或副词连用：
（1）look after 照看，照料。如：He is old enough to look after himself.他年龄足够大，能照看自己。
（2）look for 寻找。如：I looked for you just now， but I didn’t find you.刚才我到处找你，但没有找到。
（3）look around 四下环顾;到处寻找。如：He looked around but he saw nobody.他四下环顾，但什么人也没看到。
（4）look back on回想，回顾。如：They often look back on the days they spent together.他们常回顾他们在一起度过的日子。
（5）look down on看不起。