English-speaking people usually greet each other in an informal way, so you can use these common conversational greetings for friends, family, as well as people you meet in casual settings.
非正式的問候是外國人在日常交際時最常用的，你可以用以下表達和朋友、家人或是遇到的其他人進行非正式問候：
1. Hey, Hey man, or Hi
You can use 「hey」 and 「hi」 to greet someone instead of 「hello」. Both are particularly popular among younger people. While 「hi」 is appropriate to use in any casual situation, 「hey」 is for people who have already met. If you say 「hey」 to a stranger, it might be confusing for that person because he or she will try to remember when you met before! You can also add 「man」 to the end of 「hey」 when greeting males. Some people also use 「hey man」 to casually greet younger women, but only do this if you know the woman very well. Remember that 「hey」 doesn’t always mean 「hello」. 「Hey」 can also be used to call for someone’s attention.
「hey」 和 「hi」都是年輕人喜歡用的打招呼方式，區別是「hi」可以用於和任何人任何非正式場合，而「hey」往往用於熟人或已經相識的人之間。如果你對一個陌生人說「hey」，他可能會很困惑，試圖去想起你是誰。和男性打招呼的時候，我們可以說「hey man」，和女性打招呼時，如果不是非常要好的朋友，這樣說可能會冒犯到對方。此外，「hey」除了用於打招呼，也可以用來引起某人注意。
2. How’s it going? or How are you doing?
These are casual ways of asking 「how are you?」 If you’re trying to be particularly polite, stick with 「how are you?」 but otherwise, you can use these expressions to greet almost anyone. The word 「going」 is usually shortened, so it sounds more like 「go-in」. You can answer with 「it’s going well」 or 「I’m doing well」 depending on the question. Although it’s not grammatically correct, most people just answer 「good」 – and you can too. Like when responding to 「how are you?」 you can also follow your answer by asking 「and you?」.
這兩種其實是「how are you」的非正式說法，如果不是想要表達得很有禮貌，可以用這兩句話來問候任何一個人。外國人一般會把「going」讀作「go-in」。如果有人用這兩句話來和你打招呼，我們可以順著回答「it’s going well」或是「I’m doing well」，或者像外國人那樣直接說一句「good」，回答完也可以加一句「and you？」來寒暄。
3. What’s up?, What’s new?, or What’s going on?
These are some other informal ways of asking 「how are you?」 which are typically used to casually greet someone you have met before. Most people answer with 「nothing」 or 「not much」. Or, if it feels right to make small talk, you could also briefly describe anything new or interesting that’s going on in your life, before asking 「what about you?」 to continue the conversation.
這些都是用於和已經認識的人打招呼，一般人會用「nothing」 或 「not much」來回答。如果想要和對方和對方聊一會，也可以簡單地描述一下最近的趣事新鮮事來作答，最後加一句「what about you?」把對話進行下去。
4. How’s everything ?, How are things?, or How’s life?
These are some other common ways of asking 「how are you?」 They can be used to casually greet anyone, but most often they’re used to greet someone you already know. To these, you can answer 「good」 or 「not bad」. Again, if small talk feels appropriate, you could also briefly share any interesting news about your life, and then ask the person 「what about you?」 or another greeting question.
同樣是用來和相識的人打招呼。回答的時候可以說 「good」 或 「not bad」。與上一條一樣，你可以簡短地描述近況，說完可以接一句 「what about you?」 或是其他問候，就不會顯得尷尬。
5. How’s your day? or How’s your day going?
These questions mean 「how are you?」 not just right now, but how you』ve been all day. You would use these greetings later in the day and with someone you see regularly. For example, you might ask a co-worker one of these questions in the afternoon, or a cashier that you see at the grocery store every evening. 「It’s going well」 is the grammatically correct response, but many people simply answer with 「fine」, 「good」 or 「alright」. By the way, notice that 「good」, 「fine」 or 「not bad」 are perfect answers to almost any greeting question.
這兩句問候的不是當下對方的感受，而是這一天過得怎麼樣。所以一般用在下午或晚間，和定期見面的人打招呼。比如下午和同事打招呼，或是每晚都會去的雜貨店店員。回答時可以說「It’s going well」，但更多人會回答「fine」, 「good」 或 「alright」。記住，「fine」, 「good」 和 「alright」是萬能的回答方式。
6. Good to see you or Nice to see you
These casual greetings are used with friends, co-workers or family members that you haven’t seen in a while. It’s common for close friends to hug when they greet each other, particularly if they haven’t seen each other in some time; so you might use this greeting along with a hug or handshake depending on your relationship with the person.
用於向有一段時間沒見到的朋友、同事或家人打招呼，相熟的朋友之間還會加上一個擁抱。所以根據你和對方的親密程度，可以選擇配合握手或是擁抱對方。
7. Long time no see or It’s been a while
These casual greetings are used when you haven’t seen someone in a long time, particularly if you meet that person unexpectedly. How much is a long time? It depends on how often you normally see that person. For example, you could use one of these greetings if you normally see the person every week, but then don’t see them for a few months or more. Usually, these phrases are followed with a question like 「how are you」, 「how have you been?」 or 「what’s new?」
用於和許久沒見的人打招呼，尤其是在不期而遇的情況下。許久沒見是指多久？這就要取決於你們見面的頻率。比如平時每周都會見面，但這次相隔了幾個月或更久。一般說完這句還會接上「how are you」, 「how have you been?」 或「what’s new?」來問候對方。