Unidirectivity
单向性
🗣️ 情景例句
They graduated from high school last year.
他们去年高中毕业。
To carry passenger for a fare
收费运送乘客
No. He just asked if you could ring him back. Here's the number.
没有，他只问你能不能给他回一个电话。这是他的电话号码。