1、between the devil and the deep blue sea
having only two very unpleasant choices between a rock and a hard place
只能在两个非常讨厌的选项中选择，进退两难。
Their country is caught between the devil and the deep blue sea - their leaders cause great suffering, but an invasion aimed at overthrowing them would bring many other problems.
他们的国家陷入了两难的选项中，他们的领导人带来了巨大的痛苦，但是想要推翻领导人而发动袭击则会带来许多其他的问题。
For most people a visit to the dentist is the result of a choice between the devil and the deep blue sea - if you go you suffer, and if you don't go you suffer.
对于大多数人来说去看牙医是左右为难后选出的结果，如果你去，那么受罪，而如果你不去，你还是受罪。
2、blue and white
a police car; the police. (Used in cities where the police cars are painted blue and white.)
警车🚓；警察。（在警车用蓝色和白色喷漆的城市里使用）
A blue and white suddenly appeared, and I knew we were finished.
一辆警车突然出现后，我知道我们完了。
3、blue boys
the police. (see also men in blue.)
警察。（同见men in blue）
Four blue boys held me while a fifth slipped the cuffs on me.
四位警察按着我的时候第五位给我戴上手铐。
The men in blue are hammering at my door. I’m going out the back way.
警察正敲打我的门。我要从后门走了。
You can depend on the boys in blue to clean things up in this town.
你们可以靠警察来整顿这个镇子。
4、blue code of silence
An unspoken policy of concealment by police regarding the wrongdoing or illicit activity of other officers. Primarily heard in US, South Africa.
由于警方有关不当行为或其他官员的违法活动而藏匿事实的一种沉默政策。主要在美国和南非使用。
I respect the need for the police, but it's hard to trust them completely when so many stories of the blue code of silence come to light.
我尊重对警察的需要，但当这么多警方保持沉默的真相曝光后，很难再去完全信任他们了。
5、a bolt from the blue
Something unexpected or surprising.
一些预料外、令人惊讶的事情。
His sudden death came as a bolt from the blue.
他的突然去世犹如晴天霹雳。
The news that they had got married was a bolt from the blue.
他们已经结婚的消息让我目瞪口呆。
He seemed to be very happy in his job, so his resignation came as a bolt out of the blue.
他看起来在他的工作中很开心啊，所以他的辞职实在是出乎意料。
6、black and blue
if a person or part of their body is black and blue, their skin is covered with bruises (= black marks caused by being hit)
如果一个人或身体的部分是black and blue，他们的皮肤上就是有些淤青了（=由于被打而产生的黑色印记）
He was beaten black and blue at boarding school.
他在寄宿学校被打得青一块紫一块。
I’m still black and blue from my divorce.
我依然因为离婚而伤痕累累。
7、blue blood
the blood [heredity] of a noble family; aristocratic ancestry.
贵族家庭遗传的血液；贵族血统。
The earl refuses to allow anyone who is not of blue blood to marry his son.
这位伯爵拒绝任何非贵族血统的人嫁给他儿子。
Although Mary's family is poor, she has blue blood in her veins.
虽然Mary的家庭贫穷，但她仍流淌着贵族的血液。
8、turn the air blue
To speak a stream of bad language; to curse and swear. To use profane language, especially with great rapidity and intensity.
说一连串不好的话；诅咒和发誓。使用亵渎的语言，特别是说得极速很强烈。
My dad turned the air blue after he found out I'd put a dent in his car.
我爸发现我把他的车撞了一个坑后，破口大骂
9、true blue
Loyal, faithful.
忠诚的，忠实的。
You can count on her support; she's true blue.
你可以依靠她；她值得信赖。
10、have the blues
Also, feel blue . Feel depressed or sad
也用作feel blue。感到沮丧或难过。“无精打采，情绪低落”
I don't know what it is, but I find I always have the blues on Sundays.
我不知道怎么了，但我在星期天的时候情绪总是很低落。
