Formal:
* 您好 (nǐ hǎo): This is the most common and polite way to say hello, suitable for almost any situation. It literally means "you good."
Informal:
* 你好 (nǐ hǎo): This is a slightly less formal version of "您好," still widely used.
* 嗨 (hài): This is a more casual and friendly greeting, similar to "hi" in English.
* 喂 (wèi): This is used to get someone's attention, like "hello" on the phone.
Regional Variations:
* 早上好 (zǎo shang hǎo): Good morning.
* 下午好 (xià wǔ hǎo): Good afternoon.
* 晚上好 (wǎn shang hǎo): Good evening.
It's worth noting that the tone and inflection used when saying "hello" in Chinese can also convey different levels of formality and politeness.