except“从所提到的人或事物中除去,即从整体中除去一部务,表示递减的概念，含义是否定的。
bedids:表示“除了…之外，还有…“指在整体中加入一部分,表示递加的概念，舍义是肯定的。
We all went exept him .除他之外 我们都去了 。
we all went besides him.除他之外，大家也都去了。
besides常与 other /more /else等连用。
except常与all、 evey、 everyone.none nobody 、everthing、nothing连用。
He had other people to take care of beside me.
All the students in cass one went to the cinema except Li ping.
若句中没有实义动同do的某种形式，except后接动词不定式，besides后接动词ing形式。若有do的某种形式，2者后都可接动词原型。
eg. I had no choice except to obey /besides obeying his order.
she has nothing to do except /besides go with Kim.
except for 或加其他介同 besides不可以
except与besides不同
1.主体肯定和部分否定
Your composition is quite excellent except for several spelling mistake.
2. 同类事物比较
The street is empty except for several cars.
3.否定句中besides和except含义又一样
apart from 兼有2种含义 后＋n、动词ing和代词。
except可代替but. 但句中有no 、all、nobody、who、where等不定代词或疑问词时多用but。
后加宾语从句时多用except。
but for有时和except for 相同，但主要表示要不是，常用于虚拟语气表示一种假设。
,
