Monotonicity
单调性, 单一性
🗣️ 情景例句
Thanks, Grandpa. Please sit down.
谢谢你， 爷爷。请坐。
So they are content to let him go to America.
所以他们满意地让他去美国了。
A lot of things can change over twenty-one years.
21年了，许多东西都可能改变的。