Quadrivalence
n. 四价\\n[医] 四价
🗣️ 情景例句
There aren't window seats left, but a few enter seats are open.
那些靠窗的位子已没有了，但里面的位子还有。
Let me think it over,and I'll let you know later.
让我考虑一下，回头再告诉你吧。
He said that someone might be spying on the station and the pilot was ordered to keep track of the strange object.
他说可能有人正对基地进行侦察，因此命令那个飞行员跟踪那个奇怪的飞行物。