Nowadays people are facing lots of threats（威胁）all over the world.

   A serious threat to farmers in many parts of the world is erosion（侵蚀）.Erosion happens if a large area of land is cleared of trees and is then badly treated by the farmers.The rain and winds may gradually wash away,or blow away much of the topsoil.When this happens,crops of wheat and corn become weaker and weaker until nothing grows well.If erosion continues,it will turn good land into a desert.

    In the past,when erosion appeared,farmers sometimes moved to a new place to farm.Sometimes they could not move,but continued to try to grow food in the unhealthy soil.This caused them to sink into poverty.Soon some people realized that there was little rich,fertile soil in the world.The government began to try to stop erosion.

    One of the first experiments to stop erosion began in the United States in 1933.The experiment was carried out in the area of the Tennessee River.Flood and bad farming in this area had ruined the land that had once been rich.As a result,most of the people living around the Tennessee River were very poor.

The government built big dams across the river and stored the water for use during the dry season,when there was no rain.The government workers also helped the farmers fertilize their soil and to learn new farming methods which could stop erosion.

    In the beginning,the farmers were not interested.But soon,good healthy crops began to appear on the land where new methods were used.Ten years after that the crops were extremely good.The great success of this experiment led to similar projects in other parts of the world.

With the development of science and technology,people are trying to get rid of all the threats they are facing. However,it's not an easy job,because at the same time people are polluting their homeland.

    There are several ways from which to choose for you to keep your kids safe in your neighborhood. But the first step to keep your child safe in your neighborhood is to know your neighbors.

    Knowing your neighbors can save you a lot of worry. It lets you know that the car that has just driven down the street belongs to “the yellow house on the corner”, or the truck that has just driven by the playground looks unfamiliar, but the guy in the passenger seat resides two doors down. It's these simple things that keep you from going out of your mind whenever you see someone driving by where children are playing.

    But you shouldn't just know what they look like. The next step is to know them well. What do they do? How do they act? You might be OK with them driving by the playground since they live in the neighborhood, but are you OK with them being on the playground? Knowing your neighbors solves several things. First you find out what kind of people they are. This helps you know if you should let your child go out in an area where they gather. Let us face it: you do not want your child to play around people or people's children that curse (咒骂) or hit each other. Sometimes you have to protect your child against your own neighbors.

    Knowing them also makes them know you. Being neighbors is an interesting thing. You might not like them or have the same views as them, but we all usually protect those that we consider our own. If you know your neighbors, they know you. They are more likely to look after the child of the nice lady down the street in the brick (砖) house, than the people, in the house on the corner, who no one ever sees.

    Antarctica's ice white environment is going green and facing other unexpected threats. Scientists say that as temperatures go up in the polar area, invading (入侵) plants and insects, including the flies, cause a major threat.

More and more of these invaders, in the form of larvae(幼虫) or seeds, are surviving in coastal areas around the South Pole, where the temperature has risen by more than 3℃ over the past three decades. Glaciers have melted, exposing more land which has been occupied by mosses that have been found to be growing more quickly and thickly than ever before—providing potential green homes for invaders.

    “The common house flies are a perfect example of the problem the Antarctic now faces from invading species,” said Dominic Hodgson of the British Antarctic Survey. “It comes in on ships, where it exists in kitchens and then at bases on the continent. It now has an increasing chance of surviving in the Antarctic as it warms up, and that is a worry. Insects like the house flies carry bacteria that could have a deadly effect on native lifeforms.”

    The Antarctic has several native species of insects. Together with its native mosses these are now coming under increased threat from three major sources: visiting scientists increasing numbers of tourists and global warming. However, it is global warming that is the main driver of the greening of Antarctica.

    In 2015, more than 38, 000 tourists visited Antarctica. “These tourists are often very careful about not leaving waste or having mud. But they could carry seeds or larvae on their boots when they set foot on the Antarctic, “ said Hodgson.

    More and more invasive insects and plants have been found on the Antarctic and have required removal. “The insects and plants that are native to Antarctica have survived there for thousands of years,” said Hodgson, “We have got to act now if we want to save the environment.”

    You know the feeling that you have left your phone at home and feel anxious, as if you have lost your connection to the world. “Nomophobia” (无手机恐惧症) affects teenagers and adults alike. You can even do an online test to see if you have it. Last week, researchers from Hong Kong warned that nomophobia is infecting everyone. Their study found that people who use their phones to store, share and access personal memories suffer most. When users were asked to describe how they felt about their phones, words such as “hurt” (neck pain was often reported) and “alone” predicted higher levels of nomophobia.

    “The findings of our study suggest that users regard smartphones as their extended selves and get attached to the devices,” said Dr. Kim Ki Joon. “People experience feelings of anxiety and unpleasantness when separated from their phones.” Meanwhile, an American study shows that smartphone separation can lead to an increase in heart rate and blood pressure.

    So can being without your phone really give you separation anxiety? Professor Mark Griffiths, psychologist and director of the International Gaming Research Unit at Nottingham Trent University, says it is what is on the phone that counts-the social networking that creates Fomo (fear of missing out).

    “We are talking about an internet-connected device that allows people to deal with lots of aspects of their lives,” says Griffiths. “You would have to surgically remove a phone from a teenager because their whole life is rooted in this device.”

Griffiths thinks attachment theory, where we develop emotional dependency on the phone because it holds details of our lives, is a small part of nomophobia. For “screenagers”, it is Fomo that creates the most separation anxiety. If they can't see what's happening on Snapchat or Instagram, they become panic-stricken about not knowing what's going on socially. “But they adapt very quickly if you take them on holiday and there's no internet,” says Griffiths.

    Camping is a good way to spend time along with your kids and to show them how wonderful nature can be. Through camping, children can discover new things about nature, such as flowers, birds, and other small animals. Camping gives kids time to get away from all the electronics (电子) of today's culture. So it is necessary to plan exciting and enjoyable family camping trips with your children while they are young.

    When planning your family camping trip, consider the activities your kids like: games, hiking, swimming, boating, bicycling, etc. Select a camping place that has some of the activities the kids are interested in. Meal planning is an important part of your camping trip. Plan the meals together, and kids love to choose what they want to eat.

    When starting to pack for your trip, let the kids pack their own items (物品) . Each person should have his/her own sleeping bag with a luggage (行李) bag to put it in. Personal items should be packed with their sleeping bags. Encourage the kids to put their items in a certain place and always return it when they have finished using it.

    When you have arrived at your campsite, make all the camping activities a family activity, which will help children to realize how important team-work is. Everyone can have his/her own job sitting up the campsite. Meal time can be a fun time. So let the older ones help with the cooking on your outdoor camping stove while the younger ones get the picnic table ready.

    Along the river banks of the Amazon and the Orinoco there lives a bird that swims before it can fly, flies like a fat chicken, eats green leaves, has the stomach of a cow and has claw s ( 爪) on its wings when young. They build their homes about 4.6m above the river, an important feature for the safety of the young. It is called the hoatzin.

    In appearance, the birds of both sexes look very much alike with brown on the back and cream and red on the underside. The head is small, with a large set of feathers on the top, bright red eyes, and blue skin. Its nearest relatives are the common birds, cuckoos. Its most striking feature, though, is only found in the young.

    Baby hoatzins have a claw on the leading edge of each wing and another at the end of each wing tip. Using these four claws, together with the beak (喙), they can climb about in the bushes, looking very much like primitive (远古的) birds must have done. When the young hoatzins have learned to fly, they lose their claws.

    During the drier months between December and March hoatzins fly about the forest in groups of 20 to 30 birds, but in April, when the rainy season begins, they collect together in smaller living units of two to seven birds for producing purposes.