Thrombotonin
5-羟色胺
🗣️ 情景例句
If you don't know a person's last name, use 'ma'am' or 'sir'.
如果你不知道一人的姓， 你应称呼他为 'ma'am' 或 'sir' 。
The first blow is half the battle.
头炮打响，等于半个胜仗。
This was more than we could bear, so we decided to spend our last day exploring the countryside.
人多得使我们难以忍受，于是我们决定利用最后一天去乡间一游。