The indefinite articles A/AN are used when talking about a general or non-specific noun.
不定冠词A/AN指的是一般名词或非特定名词。

Where is a teacher?/A book is on the table./Did you bring a cake?
老师在哪里?/桌子上有一本书。/你带蛋糕了吗?

But unlike the definite article, A/AN can only be used with singular countable nouns. We can’t say a teachers, a books, a cakes.
但与定冠词不同,A/AN只能用于单数可数名词。我们不能说是a teachers, a books, a cakes。

Instead we use the definite article: the teachers, the books, the cakes.
取而代之的是定冠词:the teachers, the books, the cakes。

Where are the teachers?/The books are on the table./Did you bring the cakes?
老师们在哪里?/书在桌子上。/你把蛋糕带来了吗?

Remember!
记得!

In English, we use an with any noun that starts with a vowel sound, NOT with a noun that starts with a vowel. This is very important because many nouns that start with a vowel don’t have a vowel sound such as university, we say a university NOT an university. Also, many vowel sounding words don’t start with a vowel for example hour, we say an hour.
在英语中,我们使用以元音开头的任何名词,而不是以元音开头的名词。这一点非常重要,因为许多以元音开头的名词没有元音,比如大学,我们说的大学不是大学。而且,许多听起来像元音的单词都不是以元音开头的,比如小时,我们说一小时。

Below is a list of nouns you can use ‘an’ with:
下面是可以与“an”一起使用的名词列表:

an oven/an apple/an honour/an octopus/an auntie/an injury/an umbrella/an egg
烤箱/苹果/荣誉/章鱼/阿姨/受伤/雨伞/鸡蛋

Here is a list of nouns used with A:
下面是与a一起使用的名词列表:

a table/a pillow/a university/a cake/a bed/a utopia
桌子/枕头/大学/蛋糕/床/乌托邦

Here is a list of nouns used with An:
下面是与一个An连用的名词列表:

an oven/an orange/an honour/an invention/an hour/an evening
烤箱/桔子/荣誉/发明/一小时/一晚

Here are examples of how we use A and An in a sentence:
下面是我们如何在句子中使用A和An的例子:

There is a university close to here./The movie starts in an hour./There is an octopus in the water./The new house doesn’t have an oven but it has a washing machine./I need an umbrella, it’s raining outside.
附近有一所大学。/电影一小时后开始。/水里有一只章鱼。/新房子没有烤箱,但有洗衣机。/我需要一把伞,外面在下雨。

THE is called a definite article, we use the with all nouns and for specific nouns, like a certain person or a particular thing.
The被称为定冠词,我们使用与所有名词和特定名词,如某个人或某事物。

For example:
举例:

Where is the teacher?/The book is on the table/Did you bring the cake?
老师在哪里?/书在桌子上/你带蛋糕了吗?

The examples above are talking about specific things or people. In the first example, they are looking for a specific teacher, maybe a biology teacher or an English teacher. They are not looking for any teacher, they want to know where that particular teacher is.
上面的例子是谈论特定的事物或人。在第一个例子中,他们正在寻找一个特定的老师,也许是一个生物老师或者一个英语老师。他们不找老师,他们想知道那个老师在哪里。

The other two examples have a similar concept, example two is talking about a specific book on a specific table. And the third example is talking about a particular cake, maybe a birthday cake or a wedding cake.
另外两个例子有一个相似的概念,例子二是在一个特定的桌子上谈论一本特定的书。第三个例子是一个特别的蛋糕,可能是生日蛋糕或者婚礼蛋糕。