Let sleeping dogs lie – do not make trouble if you don’t have to. 　　

（打扰一只睡梦中的狗狗后果一样很严重）不要自找麻烦

e.g. There’s absolutely no point pursuing this issue. We should just let sleeping dogs lie. 　　

例句：在这个问题上深究没有意义，我们不要自找麻烦了。

上学时最早学到的一个组词是：

rain cats and dogs

倾盆大雨

关于这个俚语的由来有几种说法，当年老师给我们的解释是：十七世紀，英国的排水系统还不完善，一下大雨，就淹死很多的猫猫狗狗，所以就将倾盆豪雨说成是下猫狗雨了。现在这个词已经很少用了。

例句：
Soon it began to rain cats and dogs. Few people were seen on the street.
不久，下起了倾盆大雨。街上看不到几个人了。

Not enough room to swing a cat - Very little space
空间太小了（在旧式英语里，cat是指鞭子而不是真的猫）

例句：
You should see my new office, it’s tiny. There’s not enough room to swing a cat!
你真应该看看我的新办公室。太小了！连转身的空间都没有。

To be dog tired – to be exhausted
累趴下了

例句：
I pulled a double shift. I am dog tired.
我连上了二个班，都累趴下了。

go to the dogs – something is becoming worse than it normally was

原指食品变质，只能扔给狗吃。现引申为情况变糟或不如原来的好。

例句: I always thought my friend Pete had a good future. But then he got hooked on heroin and lost his job and his wife--I never saw a man go to the dogs so fast!
我总以为我的朋友彼徳是很有前途的。但是后来他吸上了毒品，失去了工作，妻子也走了。我从来没有看到过任何人破落得那么快的！

Let the cat out of the bag - to reveal a secret or a surprise by accident
（非故意）泄露了秘密

例句：
I bought a nice wrist watch as a surprise for my wife\'s birthday. But I\'m afraid I let the cat out of the bag--I hid it under my socks and she found it when she was putting my clean clothes away.
我给我太太买了只手表作为生日礼。我把手表藏在我的袜子底下，可是当我太太替我把乾净衣服放好的时候，她发现了那只手表。所以，我的秘密恐怕已经泻露了。

To put the cat among the pigeons – to do or say something that causes trouble and makes a lot of people angry or worried

惹出乱子 　　

例句：

Sending the most unpopular manager to talk to the team was like putting the cat among the pigeons. 　　

把一个最不受欢迎的经理派去和大家谈话一定会惹出乱子的。

Love me, love my dog - said to ?warn someone that if they ?want to be in a ?relationship with you, they must be ?willing to ?accept everything about you

这个现在多译成“爱屋及乌”

例句：

Most of Alice\'s friends didn\'t like her sister, but they accepted her because Alice insisted, "Love me, love my dog."

A cat in gloves catches no mice. - If you are too careful and polite, you may not obtain what you want.

戴着手套的猫是抓不到老鼠的。意为做事过于谨慎以至于一事无成

A dog\'s dinner or dog\'s breakfast – to make a mess
搞砸了

例句：
They made a real dog\'s dinner of the website. It\'s terrible.
他们把网站搞砸了，这太糟了。

To fight like cats and dogs – to argue and fight with someone
和某人争吵

例句：

It\'s a miracle how Sally and John manage this company. They\'re always fighting like cats and dogs.
萨利和约翰来管理公司真是个奇迹。他们总是吵得不可开交。

A cat may look at a king. - Even a person of low status or importance has rights.
意为人人平等

例句：

Curiosity killed the cat.
好奇害死猫

a dog in the manger - someone who keeps something that they do not really want in order to prevent anyone else from having it.
狗占马槽。指占着茅坑不拉屎的人。

Has the cat got your tongue? - Why aren\'t you speaking? 

猫把你的舌头叼去了吗?为什么不吭声?

例句：

The little girl had a poem to recite, but the cat got her tongue.

小女孩原本要背诵一首诗，但却紧张得说不出话来。