每天一起念念，提高听力，美化发音。
文本信息请关注公众号：esenglish 输入：晨读
示范：ES41623 = 2016年4月23日晨读
中文版本请关注订阅号：esposts
You know the row of mysterious F's numbered 1 through 12 at the top of your keyboard. These are the function keys, or as some engineers call them, "the guardian angels of the keyboard."
