楼主,你好look after表照顾,如：He looked after his sisterlook up 一般指在字典里查找单词什么的,
look up the word in the dictionary.
look for 指寻找,更倾向于找的过程,动作,（顺便提一下）
find也是寻找,但更倾向于结果.
I looked (look的过去式）for my shoes ,but I couldn't find them .
look over 多指检查,考试检查之类的
Please look over your exam paper carefully.