Null set
[计] 空集, 零集
🧩 词语组成解析
set
[sɛt]
vt. 放置，安置;使处于某种状况;设置;摆放餐具;
vi. 落山;出发;凝结;
n. 一套，一副;集合;布景;电视机;
adj. 固定的;位于…的;顽固的;安排好的;
🗣️ 情景例句
He is tough to work with.
他很难共事。
She knew that a vocation this year was out of the question.
她知道今年不可能有假期。
I'll just play it by ear.
我到时随机应变。