Difference operator
[计] 差分算子
🧩 词语组成解析
🗣️ 情景例句
I do mean it.
我的确是说真的。
Janet got mad when she heard the false story.
珍妮特听到了虚伪的话，因而大发雷霆。
Forty-two years later a tunnel was actually begun.
42年以后，隧道实际已经开始建了。