1. Number one 最重要的人（或事物）；最好的人（或事物）

eg: Many people consider themselves number one, the most important person.
很多人認為他們自己就是最好的，是最重要的一個人。

2. Look out for/Take care of number one 先為自己著想，照顧自己的利益，為自己打算

One and only 絕無僅有的；獨一無二的；有名的

eg: They are always looking out for number one and taking care of number one. It is as if they are the one and only person on Earth.
他們總是先為自己著想，只關(guān)心自己的利益，就好像他們是地球上唯一的人。

3. Pull a fast one 欺騙，搗鬼

eg: Jim only won the game because he pulled a fast one on his opponent.
吉姆因為跟對手耍了手段，才贏了比賽。

4. One in a million 百萬分之一，鳳毛麟角，百里挑一，佼佼者

eg: She's one in a million.
她是個百里挑一的人。

5. At one time 同時，曾經(jīng)

eg: At one time we met frequently.
我們過去常見面。

6. Roll up into one 合為一體；兼于一身

eg: She is a great person -- kind, thoughtful and intelligent -- all good qualities rolled up into one.
她是個很優(yōu)秀的女人——善良，體貼，聰慧——集所有可貴品質(zhì)于一身。

7. One good turn deserves another. 善須善報；要以德報德；好人應得好報。

eg: If he does you a favor, you should do him a favor. One good turn deserves another.
如果他幫你的忙，那么你就應幫他的忙，以德報德嘛。

8. Be/go back to square one 退回起點，從頭再來

eg: His papers were lost in the accident, so he had to go back to square one with the work.
他的論文在這次事故中弄丟了，只得從頭再寫。