good day

英 [ˌɡʊd ˈdeɪ]

美 [ˌɡʊd ˈdeɪ]

int. (白天见面或分手时用语)白天好，你(们)好，再见

牛津词典

exclamation

（白天见面或分手时用语）白天好，你（们）好，再见
used to say hello or goodbye politely when people first see each other or leave each other during the day
1. Good day to you.
  你好。

CONVENTION （问候用语，代替Hello及Goodbye）你（们）好，再见
People sometimes say 'Good day' instead of 'Hello' or 'Goodbye'.
1. Well, I'd better be off. Good day to you.
  好啦，我得走了，再见。

noun

Good morning! Today will be a good day.
早上好！今天会是个好日子。
Too good today, that is a good day yesterday!
过好了今天，也就是明天有了好的昨天！
I hope that all of you have a good day.
我希望你们都有美好的一天。
It is a good day to catch up on back reading and other assignments.
周日用来补上拖欠的阅读任务和其他作业的好时机。
Wednesday would be a good day for us to go running.
星期三将是我们去跑步的一个好日子。
Good day! Let me introduce myself and tell you a few things about who I am.
大家好，让我来介绍一下自己，并告诉你们一些关于我的情况。
Own good day should end immediately.
自己的好日子马上该结束了。
Good day to you, Bernard! It's a positive delight to see you
你好，伯纳德！见到你真高兴。
I'm sorry to complain so much. It's just not a good day.
我很抱歉发了这么多牢骚。今天可不是个好日子。
We did a good day's work yesterday.
昨天我们整整工作了一天。