However, depending on the context and the relationship you have with the person you're talking to, here are some options:
Informal and friendly:
* 哥们 (gē men): This literally means "brother," but it's used very casually among friends, similar to "buddy" or "bro" in English.
* 兄弟 (xiōng dì): Similar to "gē men," but slightly more formal.
* 老兄 (lǎo xiōng): Literally "older brother," but often used in a joking or playful way with someone you know well.
* 伙计 (huǒ jì): This literally means "partner," but it's often used casually among friends or colleagues.
Formal and respectful:
* 朋友 (péng you): This means "friend" and is a very common and polite way to address someone.
* 先生 (xiān sheng): This means "Mr." and is used to address someone formally, similar to "sir" in English.
Other options:
* 哎 (āi): This is a common interjection used to get someone's attention, similar to "hey" in English.
* 喂 (wèi): This is another interjection used to get someone's attention, similar to "hello" in English.
Important note: The best way to address someone is to observe how others are addressing them and use a similar level of formality.
It's also important to be mindful of the context and the person's age and social standing.