Boundary operator
[计] 边缘算子
🧩 词语组成解析
🗣️ 情景例句
Please have these clothes washed before eight o'clock tonight.
我今晚8点前请把这些衣服给洗了。
The adventure had been planned for quite a while.
那项冒险曾经作了长期的周详计划。
She went into my room and got a big surprise when she saw all those books on the floor.
她走进我的房间，当她看到地板上的那些书时，大吃一惊。