Tetragyre
四重(對稱)軸
??? 情景例句
OK. I understand. Thank you.
好吧，我懂了，謝謝你。
You must go to the moon. It's your duty.
你必須上月球去，這是你的職責。
You must weigh it carefully.
你必須仔細地稱一稱重量。