F number
焦距比数
🧩 词语组成解析
🗣️ 情景例句
In order to catch fish, you have to do this.
要钓鱼你就得这样。
To send mail(a letter)
邮寄邮件
While Alfred's little army slowly began to gather at Athelney,
阿尔弗雷德人数不多的军队开始在阿塞尔纳慢慢集结时，