Metenkephalin
n. [生化]蛋內啡肽
??? 情景例句
Sure. Would you please sign your name on the back, sir, with your passport number?
每問題。先生，請您在支票背后簽上名字和護照號碼。
I ought to write a letter.
我應該寫一封信。
How should I tell him the bad news?
我該如何告訴他這個壞消息？