1. 我们已经到了。

Wǒmen yǐjīng dào le.

We arrived already.

已经[yǐjīng] means already. It's usually used after the subject and before the predicate to indicate that an action was completed or something reached a certain degree. It’s usually used with the particle 了[le].

The structure is:

Subject + 已经[yǐjīng] + Predicate +了[le]

For example:

2. 你穿着红色的衣服，是不是？

Nǐ chuānzhe hóngsè de yīfu, shì bu shì?

Are you wearing a red dress?

着[zhe] is an aspect particle, which is usually used after a verb to indicate the continuation of a certain state.

For example:

The negative form of “verb + 着[zhe]” is adding a “没[méi]” before the verb. For example:

In the interrogative form, 没有[méiyǒu] is added at the end of the sentence.

For example:

3. 你穿着红色的衣服，是不是？

Nǐ chuānzhe hóngsè de yīfu, shì bu shì?

Are you wearing a red dress?

是不是[shì bu shì] literally means “yes or no”. If you are not sure about something, but you are somewhat certain about it, you can use 是不是[shì bu shì] to ask for confirmation. It usually comes after the subject or at the beginning or the end of a sentence.

For example:

To ask for confirmation about something:

To ask for confirmation about somebody:

是不是大卫在打电话？

Shì bu shì Dàwèi zài dǎ diànhuà?

Is David on the phone?

是不是爸爸回来了？

Shì bu shì bàba huílai le?

Is daddy coming back?

是不是你看见他走了？

Shì bu shì nǐ kànjiàn tā zǒu le?

Did you see him leave?

4. 我给你们介绍一下。

Wǒ gěi nǐmen jièshào yíxià.

Let me make the introductions.

一下[yíxià] is a quantitative phrase. It is often used after a verb to express a brief action. It can also soften the tone, so to sound more polite, you can use the structure:

Verb + 一下 [yíxià]

For example:

安娜，请你读一下这个句子。

Ānnà, qǐng nǐ dú yíxià zhège jùzi.

Anna, please read this sentence.

请等一下我。

Qǐng děng yíxià wǒ.

Please wait for me (for a moment).

我们休息一下。

Wǒmen xiūxi yíxià.

Let’s have a rest.