Quadrivalency
n. 四价
🗣️ 情景例句
Put your cards on the table.
把牌都摊到桌面上。
Whom do you want to call?
你要打电话给谁？
The question became one of whether Man could control the disease he had invented.
现在的问题是，人类能否控制住这种人为的疾病。