一、but可被看作關係代詞，引導定語從句，在句中作主語，在意義上相當於 who not或that not，具有否定意義的詞後，構成雙重否定。
如：①There is no mother but loves her children.沒有不愛自己孩子的母親。
②There was no one present but knew the story already.在場的人都知道這個故事。
二、than作關係代詞時，一般用在形式為比較級的複合句中，其結構為形容詞比較級(more)...than+從句，than在從句中作主語，相當於that，代表它前面的先行詞。(這時，它兼有連詞和代詞的性質，也有學者認為這種用法的than是連詞，後面省略了主語what。)
如：①The indoor swimming pool seems to be a great deal more luxious than is necessary.室內遊泳池過於豪華。
②He got more money than was wanted.他得到了更多的錢。 運用上述知識翻譯下列句子：
1.任何人都喜歡被讚揚。(but)
2.我們大家都想去桂林。(but)
3.沒有人不同情那些嗷嗷待哺的孩子。(but)
4.我們班上沒有一個人不想幫你。(but)
5.無論多麼荒涼，多麼難以行走的地方，人們也能把它變成戰暢(but)
6.這件事情比想像的要複雜。(than)
7.這個廣告的效果比預想的要好。(than)
8.這個問題看起來容易，實際上很難。(than)
9.他爸媽給他的零用錢總是超過他的需要。(than)
10.因為這項工程非常困難，所以需要投入更多的勞動力。(than)
答案： 1.There is no one but likes to be praised. 2. There is no one of us but wishes to visit Guilin. 3. There is no man but feels pity for those starving children.
4. There is no one in our class but wants to help you. 5. There is no country so wild and difficult but will be made a theatre of war.
6.This matter is more complex than is imagined. 7.This advertisement is more affective than is expected.
8.The problem may be more difficult in nature than would appear.
9.He got more pocket money from his parents than was demanded.
10.The project requires more labor than has been put in because it is extremely difficult.