1.受詞不計在內的排除
except (for) = excluding = save = but = other than
2.受詞包括在內，有補充意思的排除
besides = as well as = in addition to = along with = no less than = together with = plus = including = on top of
3.兩種用法皆可，須由前後文決定
aside from = apart from
Q1:
http://tw.knowledge.yahoo.com/question/question?qid=1010081408490
最佳解答與我的認知多處不同，請解惑。
Q2:
Pets are not allowed in here excepting guide dogs.
老師說excepting = except = ,excluding
何以excluding前要加逗號？
He wrote an article regarding(=concerning) environmental pollution.
regarding和concerning與excluding同樣都是現在分詞當介係詞，卻不用加逗號？
Q3:
有文法書說，but做「除了」解釋，可以當作連接詞，列兩例句如下：
An hour late for dinner, he couldn't sit down but circled the long dining room table.
He does everything in the house but put the children to bed.
這兩句but後面，第一句用過去，第二句卻用原型，原因何在？
該文法書在其他篇章又說：but後面其實是省略to的不定詞，當有do在前面時，to常被省略，但非強制，並列舉許多例子，其中又包括例句2，這不就違背連接詞前後須平行對稱的要求，而認定例句2之but在此句其實是做介係詞，後接不定詞做受詞？
更新1:
感謝天魔小雲的回答，Q3是摘自 英文常見問題大詞典(趙振才著) 從該書的多篇相關論述約可總結出兩點 1.表例外的兩詞彙but及except可與「帶to的不定詞」、「不帶to的不定詞」及「動名詞」連用，惟but接動名詞較罕見。 至於but/except的詞性是介係詞還是連接詞，語言學家沒一致的結論。 2.but/except前若有動詞do則to可選擇性省略；若是其他動詞則to不可省。
更新2:
但許多參考書明確給出了一套公式 do nothing but V(R) choose/expect/want/desire nothing but to V(R) be interested in nothing but 動名詞/名詞 enjoy nothing but 動名詞/名詞 其解釋方法正如您所說，都將but視為對等連接詞，並拆成兩句來分析。 前有do時究竟是可省還是必省就留待後人探討，至少目前我遇過的英文考題，依循這公式答案都是對的。
