Backward difference operator
[计] 后向差分算子
🧩 词语组成解析
🗣️ 情景例句
I'd like you to meet Audrey and her mother, Mrs. Cooper.
我来向你介绍， Audrey和她母亲 Cooper太太。
But last year we had a big one.
但去年下了大雪。
The men of our family waded down through our flooded meadows with boathooks, in the hope of being able to grapple a corner of the raft and pull it out of the current towards our bank.
我家的男人们手拿船篙过被水淹没草场，希望能够钩住筏子一角，将它拽出激流，拖回岸边。