Covariability
协变性
🗣️ 情景例句
Thanks for trying.
谢谢你尽了力。
It's $25.00 one way or $45.00 for a weekend excursion.
单程票价25美元，周末旅行来回票价45美元。
Look at those monkeys. What're they eating?
瞧那些猴子。它们在吃什么？