F-number
n. 数, 光圈数
🧩 词语组成解析
🗣️ 情景例句
it's going to be too late when I do remember.
等我想起来时已经太晚了。
Move over!
坐过去一点！
You must keep it a secret. You mustn't tell anybody else.
你必须保密，谁都不能讲。