1. ‘The best of both worlds’ – means you can enjoy two different opportunities at the same time.
“The best of both worlds两全其美（鱼和熊掌兼得）”——意味着你可以同时享受两个不同的机会。
“By working part-time and looking after her kids two days a week she managed to get the best of both worlds.”
“通过做兼职，每周两天照顾孩子，她设法做到了两全其美。”
2. ‘Speak of the devil’ – this means that the person you’re just talking about actually appears at that moment.
“Speak of the devil说曹操，曹操到”-这意味着你刚才说的那个人实际上就在那一刻出现。
It's bad manners of John to keep us waiting. He's never on time. Look at the clock. He's already twenty-five minutes late. Shall we go? Oh, speak of the devil, here he is now.
约翰让我们这么等，真是没有礼貌。他从来都不准时。看看那钟吧，他已经晚了25分钟了。我们要不就走吧？噢，他来了，真是说到曹操，曹操就到。
3. ‘See eye to eye’ – this means agreeing with someone.
“See eye to eye意见一致”–这意味着同意某人。
“They finally saw eye to eye on the business deal.”
“他们终于在这笔生意上达成了共识。”
4. ‘Once in a blue moon’ – an event that happens infrequently.
“Once in a blue moon千载难逢”-一个很少发生的事件。
“I only go to the cinema once in a blue moon.”
“我难得去看一次电影。”
5. ‘When pigs fly’ – something that will never happen.
“太阳从西边出When pigs fly’”-这是永远不会发生的事。
“When pigs fly she’ll tidy up her room.”
“当猪飞起来的时候，她会整理她的房间。”
6. ‘To cost an arm and a leg’– something is very expensive.
‘To cost an arm and a leg’—东西非常昂贵
“Fuel these days costs and arm and a leg.” 这些日子燃油价格贵得惊人。
7. ‘A piece of cake’– something is very easy.
‘A piece of cake’—“小菜一碟;小意思;一块蛋糕;小事一桩;轻而易举”。
“The English test was a piece of cake.” 这次英语测试很简单。
8. ‘Let the cat out of the bag’ – to accidentally reveal a secret.
“Let the cat out of the bag（无意中）泄露秘密”——无意中泄露了一个秘密。
“I let the cat out of the bag about their wedding plans.” “我把他们的婚礼计划泄露出去了。”
9. ‘To feel under the weather’ – to not feel well.感觉不佳。身体状况不好。
“I’m really feeling under the weather today; I have a terrible cold.”
我今天身体状况不佳，我感冒了。
10. ‘To kill two birds with one stone’ – to solve two problems at once.一箭双雕。
“By taking my dad on holiday, I killed two birds with one stone. I got to go away but also spend time with him.” 通过同爸爸一起度假，我一箭双雕。我既外出了，又陪伴了他。
11. ‘To cut corners’ – to do something badly or cheaply. 偷工减料
“They really cut corners when they built this bathroom; the shower is leaking.”
“他们建这间浴室时真是偷工减料，淋浴漏水了。”
12. ‘To add insult to injury’ – to make a situation worse.伤口上撒盐，更糟的是
“To add insult to injury， the car drove off without stopping after knocking me off my bike.”
“更糟的是，那辆车把我从自行车上撞下来后没停下来就开走了。”
13. ‘You can’t judge a book by its cover’ – to not judge someone or something based solely on appearance.不要仅仅根据外表来判断某人或某事。以貌取人（判断某物）
“I thought this no-brand bread would be horrible; turns out you can’t judge a book by its cover.”
“我以为这种没有牌子的面包会很可怕，最后发现你不能以外表判断。”
14. ‘Break a leg’ – means ‘good luck’ (often said to actors before they go on stage).好运。
“Break a leg Sam, I’m sure your performance will be great.”好运，萨姆，我相信你的表演会很棒的。
15. ‘To hit the nail on the head’ – to describe exactly what is causing a situation or problem.一针见血。--准确描述是什么导致了一种情况或问题。
“He hit the nail on the head when he said this company needs more HR support.”
“他说这家公司需要更多的人力资源支持，真是一针见血。”