length of day的用法和樣例：
例句
- In the temperate zone in spring, temperatures fluctuate greatly from day to day, but day length increases steadily by a predictable amount.
春天的溫帶地區，氣溫每天都變化不定，但是日照長度卻以一個可預知的數量穩步增加。 - Thus many temperate-zone birds use the increasing day lengths in spring as a cue to begin the nesting cycle, because this is a point when adequate food resources will be assured.
所以許多生活在溫帶地區的鳥類把春天裡逐漸變長的日照長度當作開始築巢的提示，因為這是能保主充足的食物來源的時候。
