(1) besides通常是包括性的，含有“连同；……之外再加上”的意味；except则是排除性的，含有“减去，除去”的意味。
- Besides half a bottle of whisky, he drank three gins and some beer.
除半瓶威士忌外，他还喝了三杯杜松子酒和一些啤酒。 - All my classmates went boating yesterday except John and Jim.
昨天，我班的同学除了约翰和吉姆外都去划船了。
(2) but也是“除了”的意思，与except接近。但在用but时，侧重点在整体。
- All were present at the party but Tom.(侧重于全体)
除汤姆外，大家都出席了晚会。 - All were present at the party except Tom.(侧重于除去部分)
大家都出席了聚会，只有汤姆除外。 - They are all agreed to the proposal put forward by Mr. Liu but Mr. Li.
他们都同意刘先生的建议，只有李先生反对。
(3) but有时用作only的同义词。
- Don't be too hard on her; she's but a child.
别对她太严厉了，她不过是个孩子。
(4) ①but常在every, any, no以及由它们构成的合成词如everywhere, nowhere, nothing, anything, nobody, all, none等之后。
- I've eaten nothing but bread and cheese since Sunday.
自星期天以来，我只吃了面包和奶酪。
②在这种情况下，but之后很少用主格，而更常用宾格me, him, her等，特别是在口语中。
- A: Who would do such a silly thing like that?
谁会做出那样的蠢事？
B: Nobody but her.
除她以外，没别人。
③但也可用主格，特别是后面紧接谓语时。
- Nobody but he/him showed much interest in the proposal.
除他外没有人对这项建议表示很大兴趣。
(5) but和except可以接动词不定式(在do nothing后通常不带to)。
- I have no choice/alternative but/except to arrive late.
除了迟到外，我别无选择。 - Nothing could save you but to reform your ways.
除了改邪归正以外，什么也救不了你。 - There was nothing to do but/except (to) wait till the meeting was over.
除了等到会议结束外，别无他法。
(6) except和but后还可接介词短语。
- I can take my holidays at any time except in July.
除了7月份以外，我什么时候休假都可以。 - He is too ill to have been anywhere but in bed.
他病得很重，只能卧床休养。 - There was no direct route but through the center of town.
除了穿过市中心外没有直达路线。
(7) but还有另外的用法，主要是在非常正式的场合。
- One cannot but admire his courage he displayed in the fight against that gang of scoundrels.
人们不能不钦佩他在跟那帮坏蛋斗争时所表现出的勇气。 - When a friend gave Jim a ticket to the concert, he couldn't help but go.
当一个朋友给了吉姆一张音乐会的票时，他忍不住去了。 - When the streets are full of melting snow, you can't help but get your shoes wet.
当大街上满是融雪时，你就无法不把鞋子弄湿。
(8) but在英式英语中还常与next, last一起用，是其特殊用法。
- I'm next but one in the queue to see the doctor; you can sit on the coach in the corridor waiting for me. (not the next one, but the one after)
在等着看病的长队里再过一个人就轮到我了，你可以坐在走廊的长椅上等我。 - My friend Jack lives next door but one. (two doors from me)
我的朋友杰克的房间与我的房间隔一扇门。
