Cách sử dụng
The expression "look up" is used when you want to search for information or find something. For example, if you don't know the meaning of a word, you can "look it up" in a dictionary. You can also "look up" a phone number or address in a directory. It can also mean to raise your head and look in a certain direction. So, if someone says "look up" to you, it means to raise your head and look at something above you.