1、(as) black as (one's) hat

Completely black; totally without light or color.

全黑；完全没有光或色彩。

The basement gives me the creeps, it's as black as my hat down there!

那个地下室让我毛骨悚然，那里一点儿光都没有！

2、a black day

a day when something very unpleasant or sad happens (usually + for ).

发生了一些很不开心或悲伤事情的一天（常用作a black day for）。

When we heard the news that David Bowie had died, we knew it was going to be a black day for all of his loyal fans.

当我们听到David Bowie去世的消息，我们就明白这对于他所有忠实粉丝来说，将会是悲痛的一天。

3、be in the black

If a bank account is in the black, it contains some money, and if a person or business is in the black, they have money in the bank and are not in debt.

如果一个银行账户in the black，说明里面还有一些钱。如果一个人或企业是in the black，那么他们在银行还有存款，没有负债。

Incredibly, we're still in the black after our holiday.

难以置信，度假之后我们在银行还有存款。

4、back the black stump

In or of an extremely remote, isolated, and/or uncivilized location, usually meaning the Australian outback."Black stump" is used colloquially as an imaginary marker of the edge of civilized settlement, though the origin of the term is uncertain. Primarily heard in Australia.

在一个相当偏远、孤立的地方，有可能是未文明化的地区，通常指的是澳大利亚的内陆。“Black stump”在口语中用作文明定居点的想象边缘线，虽然这个线通常不存在。主要在澳大利亚使用。

There are many people who still live back of the black stump, lacking access to medical care and other basic social services.

还有很多人生活在非文明地区，缺少医疗和其他基础社会服务的途径。

5、the new black

used to say that something is the most popular or fashionable colour or thing at the moment

用来指一时最流行或时尚的颜色、事物。

Designers say that green is the new black.

设计师们说绿色是新的流行色。