That little boy asked his parents why the leaves fall from the trees in autumn 9那个小男孩问他的父母为什么树在秋天掉叶子。
Leaf fall the shedding of leaves , usually associated with a fall in auxin concentration 落叶：即树叶的脱落，常伴植物激素浓度的降低。
She said : " i will die when all leaves fall off from the tree . " a old painter heard it , painting a green leave in the tree 一位老画家得知后，用彩笔画了一片叶脉青翠的树叶挂在树枝上。
The leaves fell slowly from the trees in the square . fell without wind . autumn dusk . she felt a little sick 广场上的树叶正慢慢地从枝头凋露。无风而落。秋夜幕色沉沉。她感到有点眩晕。
In winter , leaves fall and the trees look withered . it has to be like this so that the trees can grow new leaves later 冬天时，叶子都掉了，看起来好乾枯，没什么意思，不过它们应该这样，才能长出新叶。
We were wet all through , but we just took our time watching the leaves falling and floating , just like boats on the small pools of water on the roadside 我们全身尽湿，但我们仍是慢慢看着叶子掉下，像小船一样浮在路边的小水坑上。
Birds jump and sing for the sake of feeding themselves . leaves fall down to prepare new leaves to sprout . people move around diligently in order to survive 鸟跳著叫著无非为添饱肚子，树叶落著落著无非为抽出嫩芽而作准备，人动著动著也是为生存而勤快起来。
Methods we recorded labor input , fertilizer , pesticides , fanning activities and leaf fall on the soil surface in trial plots for two years 该研究通过了解作物与植物篱之间的能流交付作用，通过系统能量投入水平提高与结构优化，建立环境友好的农作系统，最终实现坡地农业的可持续。
There must be something i have to abandon after the leaves fall , is that diary written at my sixteen , or those beautiful lilylike secrets which all my life i have been keeping 一定有些什么，在叶落之后是我所必须放弃的，是十六岁时的那本日记，还是我藏了一生的，那些美丽的如山百合般的秘密。
The day is cold , and dark , and dreary ; it rains , and the wind is never weary ; the vine still clings to the moldering wall , but at every gust the dead leaves fall , and the day is dark and dreary 天冷、阴暗、沉闷；下着雨，风也刮个不停；藤还攀附着颓垣残壁，每来一阵狂风，枯叶附落纷纷，天真是阴暗而沉闷。
