（1） besides与except
前者表示“除……以外，还有……”；后者表示“从整体中除去……”
这个大家都知道，就不举例子了。
（2）except与except for
a．除去的和非除去的是同类事物，用except。
例如：
All the essays are well written except Nelson's.
Nelson的文章（除去的）和All the essays（非除去的）是同类事物，所以用except。
b．除去的和非除去的不是同类事物，用except for，并且从语气上通常表示遗憾。
例如：His essay is well written except for a few spelling mistakes.
a few spelling mistakes(除去的）和His essay（非除去的）是不同类的事物。
（3）apart from 具有多重意义：既可表示besides，也可以表示exept或exept for，还可以表示without的意思。
例如：
Apart from the cost,it will take a lot of time.(=besides)
The orphan had no one to take care of him apart from his uncle.(=except)
He has done good work,apart from a few slight faults.(=except for)
There can be no knowledge apart from practice.实践出真知．（＝without）
（4）excepting =except,但一般用于句首或用于not，without，always等词之后。
例如：
Excepting his brother,they are all right.
Everyone,not excepting myself,must share the blame.
All of us,without excepting those who know more about the subject,should study.
All my brothers com here every day,always excepting the youngest.
（5）but与except同义，但but多用在every，any，no等和由这些词构成的复合词如everything，anywhere，nobody等词以后及all，none之后。
例如：
The children go to school everyday but Sunday.
They are all gone but me.
You can get the book anywhere but here.
There is no one but me.
Who but George would do such a thing?