1. 你好!

Nǐ hǎo!

Hello!

你好[nǐ hǎo] is a very common sentence to greet others in Chinese. But note that, it is usually used when two people meet for the first time. If you say it to your friends and acquaintances, it will be a little bit weird.

Learn more: Do Not Always Say 你好 Nǐ hǎo When Greeting - Speak like a Native

2. 老师，您好！

Lǎoshī, nín hǎo!

Hello, teacher!

您[nín] is a polite way to say 你[nǐ]. You can use 您[nín] to address people whom you respect, such as your boss, teachers or the elderly person.

3. 你们好！

Nǐmen hǎo!

Hello, everyone!

们 [men] is the affix for plural in Chinese. It can be only used with nouns or pronouns to express people or animals.

For example: