[求小学生英语小故事要求3到4分钟用于演讲]Sun the Ice Once a simpleton's wife told him to buy some ice. Two hours later, he didn't come back. She wanted to know why he didn't come back and went out to h...+阅读
Never too old to learn, never too late to turn.亡羊补牢，为时未晚。
There was once a shepherd to the sheep and found that the sheep pen was broken, someone advised him to fill the hollow as soon as possible, he did not listen, the next day the sheep indeed stolen. So he finally sheep pen good repair.
从前有一个人他家里养了许多羊。
一天，羊圈上的栏杆上塌了一个洞，邻居看见了，就提醒他赶快修羊圈，他呢，摇摇头说：“只有一个小小的洞，没关系的，过几天再修吧。”邻居没办法，只好走开了。
当他准备修补羊圈的栏杆，顺便看看小宝贝羊羔长的怎么样时，发现羊跑掉了不少，没剩几只了，他看到这番景象，不禁伤心地大哭起来：“我的羊儿呢？哇……哇……”
羊儿不见了，是因为羊圈上栏杆的洞修得太迟了。你一旦发现，就要及时修补，否则羊就一只一只地跑走了，你现在修补还不算晚，还能挽救剩下的羊只
有适合小学五年级参加英语故事比赛的小故事吗
为什么人夜晚睡觉不会口渴 The body's internal clock helps to regulate a water-storing hormone so that nightly dehydration or trips to the toilet are not the norm, research suggests.In an article published in Nature Neuroscience today, neurophysiologists Eric Trudel and Charles Bourque at the Research Institute of the McGill University Health Centre in Montreal, Canada, propose a mechanism by which the body's circadian system, or internal clock, controls water regulation1. By allowing cells that sense water levels to activate cells that release vasopressin, a hormone that instructs the body to store water, the circadian system keeps the body hydrated during sleep.＂We've known for years that there's a rhythm of vasopressin that gets high when you're sleeping. But no one knew how that occurred. And this group identified a very concrete physiological mechanism of how it occurs,＂ says Christopher Colwell, a neuroscientist who studies sleep and circadian rhythms at the David Geffen School of Medicine at the University of California, Los Angeles.The body regulates its water content mainly by balancing water intake through thirst with water loss through urine production. People don't drink during sleep, so the body has to minimize water loss to remain sufficiently hydrated. Scientists knew that low water levels excite a group of cells called osmosensory neurons, which direct another set of neurons to release vasopressin into the bloodstream. Vasopressin levels increase during sleep; clock neurons, meanwhile, get quieter. Trudel and Bourque tested the idea that lower clock-neuron activity might allow osmosensory neurons to more easily activate vasopressin-releasing neurons, which would mean more water retention and less urine production during sleep.To do this, they isolated thin slices of rat brain containing intact sensory, vasopressin-releasing and clock neurons. Even when removed from the brain, clock neurons continue to mark time.The duo then stimulated the sensory neurons and recorded any electrical activity in the vasopressin-releasing neurons to monitor communication between the two cell groups. The researchers then moved on to look at the effect of the clock cells on this pathway. When they did not activate the clock cells during the 'sleep' part of their cycle, it was easier for the sensory cells to communicate with vasopressin-releasing cells. Conversely, when they activated the clock cells, this communication decreased markedly.The results suggest that clock cells function as a dimmer switch for water control. When their activity is high, they prevent sensory cells from instructing secretory cells to release vasopressin. Then, when clock cells are less active, sensory cells can easily instruct secretory cells to release vasopressin, ensuring that the body holds on to its water reserves.Colwell points out that the study was done in rats, which are nocturnal. Although the vasopressin cycle and clock-neuron activity are similar in rats and humans, the question of whether the same mechanism occurs in animals that sleep at night remains to be answered.＂We show this for this one circuit, but it's possible that clock neurons regulate other circuits in a similar manner and this remains to be studied,＂ says Bourque. He speculates that future studies might reveal whether the same mechanism regulates hunger, sleepiness and other aspects of physiology related to circadian rhythms.
以下为关联文档：
3分钟幽默英语小故事初中1。The City Mouse and the Country Mouse Once there were two mice. They were friends. One mouse lived in the country; the other mouse lived in the city. After ma...
小学生英语小故事 2分钟左右The country Maid and Her Milk Can 村姑和牛奶罐 A country maid was walking along with a can of milk upon her head,when she fell into the following train of refle...
英语故事带翻译幽默 3分钟左右The Old Cat An old woman had a cat. The cat was very old; she could not run quickly, and she could not bite, because she was so old. One day the old cat saw a m...
英语小故事3分钟Very Pleased to Meet You During World War II, a lot of young women in Britain were in the army. Joan Phillips was one of them. She worked in a big camp, and of...
3分钟英语小故事On Mother's Day last year ,Peter tried to buy a present for his mother. He went into a shop, which had a sign out side. “Second hand clothes, bought and sold....
求一个3分钟左右的英语小故事Dick was seven years old, and his sister, Catherine, was five. One day their mother took them to their aunt's house to play while she went to the big city to bu...
英语小故事带翻译3分钟Fox and cock One morning a fox sees a cock.He think,＂This is my breakfast.'' He comes up to the cock and says,＂I know you can sing very well.Can you sing for me?'...
小学3年级的英语笑话3分钟Mother sent Tommy to the store across the street to buy a good box of matches.When Tommy came back,mother asked him,”Did you buy a good box of matches?” “Yes...
小红帽英语故事 200字左右 3分钟的时间我修改过了，自己写了点，你看看吧~~ Once upon a time, there was a little girl. Her name was Little Red Riding Hood. One day, her grandma was ill. Little Red Riding H...
