Formal:
* 您好 (nǐ hǎo) - This is the most common and polite way to say hello. It's suitable for all situations, from meeting someone for the first time to greeting a superior.
* 您早 (nín zǎo) - Good morning. This is a more formal way to greet someone in the morning.
* 您下午好 (nín xiàwǔ hǎo) - Good afternoon. This is a more formal way to greet someone in the afternoon.
* 您晚上好 (nín wǎnshàng hǎo) - Good evening. This is a more formal way to greet someone in the evening.
Informal:
* 你好 (nǐ hǎo) - This is a more casual way to say hello, and is appropriate for friends and family.
* 早上好 (zǎoshang hǎo) - Good morning. This is a casual way to greet someone in the morning.
* 下午好 (xiàwǔ hǎo) - Good afternoon. This is a casual way to greet someone in the afternoon.
* 晚上好 (wǎnshàng hǎo) - Good evening. This is a casual way to greet someone in the evening.
* 嗨 (hāi) - Hey. This is a very informal greeting, similar to "Hi" in English.
Other greetings:
* 好久不见 (hǎo jiǔ bù jiàn) - Long time no see.
* 你好吗 (nǐ hǎo ma)? - How are you?
It's important to note that the tone of voice can also affect the meaning of a greeting. A polite and respectful tone is generally preferred in formal situations.