1.A Dark Horse  – someone who doesn't reveal their hidden talents and surprises people when they discover them1.
A Dark Horse ——黑马，隐藏的才能被发现后让人们大吃一惊的人
Jean is a dark horse, isn't she? All these months we thought she was quietly working in the back office when in actual fact she was writing a bestselling novel.
琼真是匹黑马，不是吗？这几个月我们以为她在办公室里安静地工作，事实上她在写一部畅销小说。

2.Closing the Stable Door After the Horse Has Bolted  - Trying to stop something bad from happening when it has already happened and cannot be changed2.
Closing the Stable Door After the Horse Has Bolted ——想要阻止坏事发生，但已经太迟了
Introducing tighter security measures after the break in seems to me like closing the stable door after the horse has bolted.
在被破门而入之后再引进更牢固的安全措施，在我看来为时已晚。

3. To Drive a Coach and Horses Through Something – to expose the weak points or gaps in an argument3.
To Drive a Coach and Horses Through Something——在争议中暴露弱点或漏洞
The CFO drove a coach and horses through the company’s plans for expansion.
首席财务官暴露了公司扩张计划中的弱点。

4. To Beat a Dead Horse – to waste time doing something that has already been done4.
To Beat  a Dead Horse——在已经发生的事上浪费时间
Do you think It’s worth me writing to a few more recruitment agencies, or am I just beating a dead horse?
你觉得我再给一些招聘公司写信值不值？还是我只是在浪费时间？

5.To Get off Your High Horse - to stop acting as if you are better or more intelligent than other people5.
To Get off Your High Horse——不再表现得像是你比别人更好、更聪明
“If you would get off your high horse for one minute and listen to your colleagues, you would find that they have some great ideas for this project”.
“如果你能有一会放下架子，听听同事的意见，你会发现他们对于这个项目有这非常出色的想法。”

6. Don’t Put the Cart Before the Horse (Proverb) – Do not do things in the wrong order. It implies that someone is impatient.6.
Don’t Put the Cart Before the Horse —不要本末倒置，做事顺序不要颠倒。暗指某人不耐烦。
There’s no point trying to write the report when you haven’t got a clear idea of what to write. You don’t want to put the cart before the horse.
在你还没有清晰的想法之前就去写报告是没有意义的。你不会想要本末倒置的。
7.To Look a Gift Horse in the Mouth – to be ungrateful to someone who gives you something.
To Look a Gift Horse in the Mouth——对别人给你的东西挑三拣四
“I wouldn’t look a gift horse in the mouth. I would accept that promotion”.
“我不会吹毛求疵的。我会接受升职。”

8. Horses for Courses – something you say to mean that it is important to choose the right people with the suitable skills to do a chosen activity8.
Horses for Courses——意思是挑选有匹配才干的合适人选做特定的活动十分重要
“Ah well, it’s horses for courses. Just because he is an IT expert doesn’t mean that he is an expert in everything to do with computers”.
“好吧，术业有专攻。他是IT专家不能说明他在和电脑有关的所有领域里都是专家。”

9. To Get It Straight From the Horse’s Mouth – to get information directly from the original source9.
To Get It Straight From the Horse’s Mouth——从信息源直接得到信息，一手信息
Keith: “Where did you hear about the takeover?” Peter: “I got it straight from the horse’s mouth.”
基斯：“你从哪里听说收购这件事的？”彼得：“我亲耳听见的。”

10. To Back the Wrong Horse - to support someone or something that cannot win or succeed10.
To Back the Wrong Horse——站错队，支持了不可能成功的人或事
Oh well, I guess we should have known that this marketing campaign wouldn’t work. We just backed the wrong horse this time.
哦，我们本来应该明白这次市场活动不会成功的。我们只是失策了。