Four operations
四则运算
🧩 词语组成解析
four
[fɔr]
num. 四;四个;第四;
n. 四的;四个一组之物;
n. 运作；运营；业务操作（operation的复数）
🗣️ 情景例句
Yes. It's the anniversary of one of our important revolutionary movements.
是的。它是中国一个重大革命运动的纪念日。
My father used to smoke, but now he doesn't.
w
You're not busy doing anything, are you?'
你不忙，是吗？”