To say "hello again" in English, you can say "Nice to see you again" or "It's good to see you again." The phrase comes from the English greeting "hello," which is used to greet someone when you meet them or see them again after a period of separation.

Here are some examples of how you can use this phrase in English:

"Nice to see you again, John. How have you been?"

"It's good to see you again, Mary. What brings you here?"

"Hello again, Tom. It's been a while since we last saw each other."

In Chinese, you can say "再次见到你真好" or "见到你又是一种享受" to mean "nice to see you again" or "it's good to see you again."