The African elephant, the largest land animal remaining on earth , is of great importance to African ecosystem(生态系统). Unlike other animals, the African elephant is to a great extent the builder of its environment. As a big plant-eater, it largely shapes the forest-and-savanna(大草原)surroundings in which it lives, therefore setting the terms of existence for millions of other animals that live in its habitat(栖息地).

    It is the elephant's great desire for food that makes it a disturber of the environment and an important builder of its habitat. In its continuous search for the 300 pounds of plants it must have every day, it kills small trees and underbushes, and pulls branches off big trees. This results in numerous open spaces in both deep tropical forests and in the woodlands that cover part of the African savannas. In these open spaces are numerous plants in various stages of growth that attract a variety of other plant-eaters.

    Take the rain forests for example. In their natural state, the spreading branches overhead shut out sunlight and prevent the growth of plants on the forest floor. By pulling down trees and eating plants, elephants make open spaces, allowing new plants to grow on the forest floor. In such situations, the forests become suitable for large hoofed plant-eaters to move around and for small plant-eaters to get their food as well.

    What worries scientists now is that the African elephant has become an endangered species. If the elephant disappears, scientists say, many other animals will also disappear from vast areas of forest and savanna, greatly changing and worsening the whole ecosystem.

    Parents who help their children with homework may actually be bringing down their school grades. Other forms of parental involvement, including volunteering at school and observing a child's class, also fail to help, according to the most recent study on the topic.

    The findings challenge a key principle of modern parenting where schools expect them to act as partners in their children's education. Previous generations concentrated on getting children to school on time, fed, dressed and ready to learn.

    Keith Robinson, the author of the study, said, "I really don't know if the public is ready for this but there are some ways parents can be involved in their kids' education that leads to declines in their academic performance. One of the things that was consistently negative was their parents' help with homework." Robinson suggested that may be because parents themselves struggle to understand the tasks."They may either not remember the material their kids are studying now, or in some cases never learnt it themselves, but they're still offering advice."

    Robinson assessed parental involvement performance and found one of the most damaging things a parent could do was to punish their children for poor marks. In general, about 20% of parental involvement was positive,  about 45% negative and the rest statistically insignificant.

    Common sense suggests it was a good thing for parents to get involved because "children with good academic success do have involved parents", admitted Robinson. But he argued that this did not prove parental involvement was the root cause of that success. "A big surprise was that Asian-American parents whose kids are doing so well in school hardly involved. They took a more reasonable approach, conveying to their children how success at school could improve their lives."

    Every day, we are inching closer to some kind of artificial intelligence. Advances in big data, machine learning and robotics are going to give us a world where computers are effectively intelligent in terms of how we deal with them. Should you be scared by this? Absolutely, but not in the usual “robot overlords” (机器人帝国) kind of way. Instead, the real fear should be about getting human beings wrong, not getting AI right.

    The key to the technology is the ability of computers to recognize human emotions based on the ‘‘activation” of muscles in the face. A computer can identify the positions of facial muscles and use them to infer the emotional state of its user. Then the machine responds in ways that take that emotional state into account.

    One potential application of it is to provide “emotional robots” for the elderly. Having a machine that could speak in a kind way would comfort a lonely older person. That is a good thing, right? But that won't also relieve us from questioning how we ended up in a society that takes care of the elderly because we don't know what else to do with them? Can't we have more humane solutions than robots?

    “Emotion data” aren't the same thing as the real and vivid emotional experiences we human beings have. Our emotions are more than our faces or voices. How can they be pulled out like a thread, one by one, from the fabric of our being?

    Research programs can come with much philosophical concern, too. From the computers' point of view, what the computing technology captures are emotions, but at its root is a reduction of human experience whose outward expressions can be captured algorithmically (计算上). As the technology is used in the world, it can reframe the world in ways that can be hard to escape from.

    The technology will clearly have useful applications, but once it treats emotions as data, we may find that it is the only aspect of emotion we come to recognize or value. Once billions of dollars floods into this field, we will find ourselves trapped in a technology that is reducing our lives. Even worse, our “emotion data” will be used against us to make money for someone else. And that is what scares me about AI.

    You may know about “junk food” like French fries. But do you know about “junk sleep”?

    Recently, a British survey found that electronic(电子的) products in teenagers bedrooms are affecting(影响)their sleep.

    The survey was done among 1,000 British kids from 12 to 16. It found that 30 percent of them got just 4 to 7 hours sleep every day. But doctors say they need 8 to 9 hours.

    Almost a quarter of the kids said they fell asleep more than once a week while watching TV, listening to music or using other electronic products.

    “This is very worrying.” said Dr Chris Idzikowski, a British expert, “We call it 'junk sleep', it means you don't get enough sleep and the quality of the sleep is bad, too. If you don't get good rest, you don't perform well in school the next day.”

    The survey found that 40 percent of the kids felt tired each day, with girls between 13 and 16 feeling the worst. Nearly all the teenagers have a phone, Mp4 or TV in their bedroom. And many of them have all three.

    We're surrounded by chemistry in everyday life. Sometimes it is easy to see, like when your science teacher conducts a big experiment in class. At other times, it can be extremely hard to see everyday chemistry at work, but nearly everything you touch or use has some element of chemistry in it.

    Something as simple as toothpaste contains at least three chemicals, if not more. It is the mixture of them and its chemical reaction that keeps your teeth clean. Other things you use every day are created by chemistry, such as hair products, shampoo and soap. Adding detergent (洗涤剂) to water involves chemistry. Without chemistry, we would never have realized that we need soap to get the oil out of clothes or skin.

    Chemistry not only helps us make products for use, but it also helps us understand the world around us. Chemistry helps us understand what the ozone layer (臭氧层) is and how it protects us. Chemistry also gives us sunscreen to protect us from the sun. Thanks to chemistry, we know bleach (漂白剂) can't be mixed with vinegar, because it can produce poisonous gas. Without chemistry, we wouldn't have had fireworks displays on important days like the Spring Festival.

    Chemistry plays a big role in food preparation. Cooking food causes it to go through a chemical change. That is why cooked food often tastes different from raw (生的) food. Baking is a great example of chemistry. Too much or too little of any ingredient makes a difference to the result of baking, for example, the dough (面团) won't rise or the cake will be flat.

    Chemistry isn't something that just lives in a lab; it's something that you come across hundreds of times every day. If you know how chemistry works, you will get a greater comprehension of the science behind some of the simplest looking things.

You should try your best to create your own family library so that you and your family are always learning. "It is a great mistake to think that education is finished when young people leave school. Education is never finished even if you grow older," said Mrs Child in The Mother's Book. "Collecting a library of books in your home is really helpful to your family.”

"What is really interesting about having so many books in your home is that a book you purchase has a chapter about the deeper knowledge of your favorite subject at school," said a university graduate. Researchers in a study tries to identify what parents do has an influence on how well their children do on standardized tests. One positive aspect they find is the availability of a large number of books at home. This has a stronger connection, especially when you read to your children every day. The more books your older kids have access to at home, the more likely they are just to be reading for fun, rather than having to wait for weekly trips to the library.

John Henry, one educated parent, said, "I have been homeschooling my children using the philosophy of A Thomas Jeffer son Education. This philosophy of learning is based on the reading of classic books." Clinton Fadiman said, "When you reread a classic, you do not see more in the book than you did before; you see more in you than before." Classic books also make you smarter and wiser! The wisdom comes in the examples in the lives of the characters.

"It is within your power to guide your youth in their reading and to cultivate in their hearts a desire for good books. It is the most unfortunate if a person is not possessed with the desire for good reading. The reading habit, like charity, should begin at home," said Mrs Child.