It cannot be used to mean hello outside of a phone conversation, however. It’s placed in front of the verb that it modifies: He just left. He has just left. Study notes: This is often used to give one’s advice or opinion based on a conditional. If it's you (we are talking about), you can do it. Examples: A Japanese person wouldn't do such a thing. If you have to get work done, hurry up and do it. If I like the flower, I'll buy it. I want to go there someday. I want to go there again someday. I want to go to Japan someday. I couldn't sleep. I couldn't sleep at all. I never closed my eyes all night. Go and wake your brother. I awoke from a dream. Call me early. Don't forget to call me tomorrow. I can't conceive how you can sleep so long. China itself is no longer keeping its distance from its fellow-Chinese who have chosen to make their living abroad, and it is possible that this new, more diplomatic face of China will become openly influential, perhaps even hegemonic.