1.Pass the buck----shift the responsibility to someone else 推卸责任
We all know that buck is informal American English for a dollar. Indeed, it can also be used for an Australian dollar, a New Zealand dollar, a South African rand, and an Indian rupee – but none of those senses are related to pass the buck.
This particular buck is ‘an article placed as a reminder in front of a player whose turn it is to deal at poker’ – which means passing it make much more sense. This item also gives us the phrase the buck stops here; both figurative phrases have moved far beyond their poker origins.
这里的buck是特指“在纸牌游戏中当轮到某人发牌时，放置在玩家面前作为提示的物品”，这样传递这个物品便有了更多的含义。这件物品同样给了我们另一个短语the buck stops here（责无旁贷）；这两个比喻意味的短语，其含义已经远远超出了扑克的起源。
2.Turn over a new leaf----start to act or behave in a better or more responsible way 改过自新
It has nothing to do with foliage,but relates to another common use of leaf: one of the pages in a book. A similar derivation gives us to take a leaf out of someone’s book, meaning ‘imitate or emulate someone in a particular way’.
这个短语和叶子无关，而和leaf另一个常见的含义有关：书中的一页。类似的引申出to take a leaf out of someone’s book这个短语，表示“模仿某人”。
3. Push the envelope----to approach or extend the limits of what is possible 接近甚至超越限度
This envelope isn’t the sort you’d put letters in.Push the envelope was originally aviation slang relating to graphs of aerodynamic performance and exceeding the set of limiting cobinations of speed and altitude.
这个信封并不是我们装信的信封。Push the envelope最初是航空俚语，与空气动力性能的图表相关并且超过速度和高度的合并限制。
4. Ring the changes----vary the ways of expressing or doing something 以不同的方式做(或说)同一件事
This phrase has nothing to do with pen and paper. Instead, it came originally with allusion to bell-ringing and the different orders in which a peal of bells may be rung.