你好！ Hello! / Hi!
您好！ Hello! / Hi!

Explain:
你 you
您 you
好 good
Notes：
“你好！” means “Hello! / Hi!” It is a common everyday greeting. You may use this phrase to the people not elder than you or less important than you, anywhere at any time. When you want to say hello to the aged people, your boss, your parents, your teachers or some other respectable persons, you are supposed to use “您好” instead, which is more respectful.

你们好!
Hello, everybody!
Explain:
你们 you(pl.)
好 good
Notes：
“你们好！” means “Hello，everybody!” “们” is a symbol of plural, for example, 我(I)—我们(we)，他(he)—他们(they). When you go to a dinner, you may say this to the people at the table. It’s commonly used on some informal social occasions.

大家好!
Hello, everyone!
Explain:
大家 everyone
好 good
Notes:
“大家好！” means “Hello, everyone!” This is generally used to address the audience at a lecture， a meeting, or on other formal occasions.
Another difference between Chinese and English pronunciation is that you read English word by word^ while Chinese，character by character^ So you need a pause between the characters：大—家—好. Don't pronounce [dΛʤΛhau]. You can't treat them as one English word.

早！
Good morning!/ Morning.
早上好!
Good morning!/ Morning.
Explain:
早上 morning
好 good
Notes:
“早上好!” means “Good morning!” You may also simply say “早！” It has the same meaning as “Morning.” “早上好！”， is more formal, generally spoken to respected persons or to customers. “早！” is frequently used in everyday life, when you just want to say a quick greeting to a friend, a colleague or a classmate in the morning.

晚上好!
Good evening!
Explain:
晚上 evening
好 good
Notes：
“晚上好！” means “Good evening! ” You may use this to say hello to people after sunset in the evening.

嗨！Hi!
嘿！Hi!
Explain:
嗨 hi
嘿 hey
Notes：
"嗨!" means "Hi!" "嗨" is equal to "嘿!" You may use them to say hello to anyone whom you are familiar with. They are often used by young people, which sound very friendly.

好久不见!
Long time no see. / I haven't seen you for a long time.
Explain:
好久 a long time
不见 haven't seen
Notes:
“好久不见！” means “I haven’t seen you for a long time.” When you meet a friend whom you haven't seen for some time, you can use this sentence to show your consideration of him. Then you may keep talking about how you are going along.

见到你很高兴。
Nice to meet/see you.
Explain:
见到 see/meet
很(彳+艮) very
高兴= happy
Notes：
“见到你很高兴。” means “Nice to meet/ see you generally used among adults, on formal occasions.

去哪儿？
Where are you going?
Explain:
去 going
哪儿 where
Notes：
“去哪儿？” means “Where are you going?” Western people don't feel happy when addressed this way# He thinks this is a matter of his own, and other people should not ask. But in China, when someone asks you this question, he doesn’t really want to know where you are going. He just wants to be polite to you, and you don't need to tell a lot of things to him. You just simply answer, “出去一下。” which means "I'm going to some place.

欢迎光临!
Welcome!
Explain:
欢迎：welcome
光临：come/ attend
Notes：
“欢迎光临！” means “ Welcome!” This is a friendly greeting. When you come to a store department, a hotel, a restaurant, a coffee bar etc., you can always hear it. You may say “Thank you.” or just give them a smile to be polite as a reply.