It is reported that conservation groups in North America have been arguing about the benefits and dangers of wolves. Some groups believe wolves should be killed. Other people believe wolves must be protected so that they will not disappear from the wilderness(荒野).

For Killing Wolves

    In Alaska，the wolf almost disappeared a few years ago，because hunters were killing hundreds of them for sport. However, 1aws were established to protect the wolves from sportsmen and people who catch the animals for their fur．So the wolf population has greatly increased. Now there are so many wolves that they are destroying their own food supply.

    A wolf naturally eats animals in the deer family. People in the wilderness also hunt deer for food. Many of the animals have been destroyed by the very cold winters recently and by changes in the wilderness plant life．When the deer can't find enough food，they die.

    If the wolves continue to kill large numbers of deer, their prey(猎物) will disappear some day. And the wolves will, too. So we must change the cycle of life in the wilderness to balance the ecology. If we killed more wolves, we would save them and their prey from dying out. We'd also save some farm animals.

    In another northern state, wolves attack cows and chickens for food. Farmers want the government to send biologists to study the problem. They believe it necessary to kill wolves in some areas and to protect them in places where there is a small wolf population．

Against Killing Wolves

    If you had lived long ago，you would have heard many different stories about the dangerous wolf．According to most stories，hungry wolves often kill people for food．Even today，the stories of the “big bad wolf” will not disappear．

    But the fact is wolves are afraid of people, and they seldom travel in areas where there is a human smell．When wolves eat other animals，they usually kill the very young, or the sick and injured. The strongest survive. No kind of animal would have survived through the centuries if the weak members had lived. And has always been a law of nature.

    Although some people say it is good sense to kill wolves，we say it is nonsense! Researchers have found wolves and their prey living in balance．The wolves keep the deer population from becoming too large, and that keeps a balance in the wilderness plant life.

    The real problem is that the areas where wolves can live are being used by people. Even if wilderness land is not used directly for human needs, the wolves can't always find enough food. So they travel to the nearest source, which is often a farm. Then there is danger. The “big bad wolf” has arrived! And everyone knows what happens next.

    Alaska's state fair, which runs until September 5^th, began as a celebration among residents of the Mantanuska Colony, a project under which 200 farm families were moved to Alaska to see whether agriculture could be possible in the coldest state. The state fair lives on, but little more than a decade after the start of the project most of the participants had abandoned their farms. The project was widely seen as a flop.

    In this state, glaciers cover 300 times more acres than farms. Only 5% of the food consumed is grown locally, compared with 81% nationwide. The growing season is short and summer temperatures chilly. Tomato plants wither(凋谢). Fruit trees, in most parts of the state, are just a dream.

    Enter the high tunnel: a greenhouse consisting of a metal frame with plastic stretched across it. Its few millimeters of plastic separate crops inside from the great outdoors. But this is enough for Alaskan growers to produce tomatoes as well as sweetcorn, peaches and kiwi fruit, and to boost production of crops by a quarter or more.

    In a place where no one blinks(眨眼) if you call yourself a fisherman, boat captain or gold miner, an increasing number of Alaskans are thinking of themselves as people who grow food. Since the start of the programme, the number of farms registered(登记)with the state has nearly doubled. Local restaurants have begun shaping their menus around what neighboring farms can grow.

    Eight decades ago, the Mantanuska Colony tried to turn farmers into Alaskans. Today, the high tunnels are turning Alaskans into farmers.

    Have you heard an old saying “The grass looks greeener on the other side of the fence”? It means other places often look better, more interesting than the place where you live. “Let's go to KFC for dinner and then watch some Japanese cartoons!” We all know it: more and more Chinese kids love American and Japanese food and movies. Some people worry that young Chinese are beginning to feel that way. They see young Chinese ignoring (忽视) Chinese culture and, instead, buying Japanese cartoon books, watching Korean soap operas and even celebrating Western holidays.

    Foreign books and soap operas are good, but Chinese writers and actors are just as good. As for holidays, Christmas is nice, but it can never have the meaning for Chinese that Spring Festival has, and the West has nothing to compare with the Mid-Autumn Festival. China has lots of cool things in its culture: calligraphy, Bejing Opera, quick meals on the streets, and even Jay Chou! And let's not forget the part of Chinese culture I like best: its friendliness. Not all countries are as warm as China.

    It's good to enjoy other cultures and learn from them, but they can never replace your own culture. It's good to look on the other side of the fence, but make sure you take a good long book. You will find that the grass isn't always greener.

    Although some people become worried about that, I don't think they should. Will we get more powerful without learning from other countries? Will Chinese people live more happily without American fast food? Besides, it's fun to learn about different cultures. Chinese kids can learn about other cultures and have fun, but they also need to learn more about their own culture. Be proud of Chinese culture and of being Chinese!

    Last week, Vodafone started a test of the UK's first full 5G service, available for use by businesses in Salford. It is part of its plan to trial the technology in seven UK cities. But what can we expect from the next generation of mobile technology?

    One thing we will see in the preparation for the test is lots of tricks with the new tech. Earlier this year, operators paid almost £ 1.4 billion for the 5G wavelengths, and to compensate for that cash, they will need to catch the eye of consumers. In September, Vodafone used its bit of the range to display the UK's first hologram (全息) call. The Manchester City captain Steph Houghton appeared as a hologram in Newbury. It isn't all holograms, however: 5G will offer faster internet access, with Ofcom (英国通讯管理局) suggesting that video that takes a minute to download on 4G will be available in just a second.

    The wider application is to support connected equipment on the "internet of things" -not just the internet-enabled fridge that can reorder your milk for you, but the network that will enable driverless cars and delivery drones (无人机) to communicate with each other.

    Prof William Webb has warned that the technology could be a case of the emperor's new clothes. Much of the speed increase, he claims, could have been achieved by putting more money in the 4G network, rather than a new technology.  Other different voices have suggested that a focus on rolling out wider rural broadband access and addressing current network coverage would be more beneficial to the UK as a whole.

    Obviously, 5G will also bring a cost to consumers. It requires a handset for both 5G and 4G, and the first 5G-enabled smart phones are expected in the coming year. With the slow pace of network rollout so far, it is likely that consumers will end up upgrading to a new 5 G phone well before 5 G becomes widely available in the next couple of years.

    A food additive (添加剂) is any substance that is added to food. Many people are put off by the idea of "chemicals in food." The truth is that all food is made up of chemicals. Natural substances like milk, as well as man-made ones like drinks on sale in the market, can be described by chemical formulas. Some chemical substances are indeed harmful, but a person who refused to consume any chemicals would find nothing to eat.

    The things we eat can be divided into natural and man-made substances. Some people feel that only natural foods are healthy and that all man-made ingredients are to be avoided. But many natural chemicals, found in plants and animals, are harmful when eaten, and some laboratory-made substances increase the nutritional value of food. Other chemicals have natural and man-made forms that are exactly alike: vitamin C is vitamin C, whether it comes from a test tube or from an orange. Like "chemical", "man-made" doesn't necessarily mean "not fit to eat".

    Food additives are used for many reasons. We add sugar and salt and other things to foods we prepare at home to make them taste better. Food producers have developed a range of additives that stabilize, thicken, harden, keep wet, keep firm, or improve the appearance of their products. Additives can make food more convenient or nutritious, give it a longer shelf life, and make it more attractive to the consumer, thus increasing the sales and profits of the producers.

    Food additives are presently the centre of a storm of serious argument. Food producers have been known to use additives that have not been proved safe; some substances in common use have been proved unsafe and have been taken off the market. Many people feel there's a risk of eating food to which anything has been added. But food additives are now regulated by the FDA of the federal government, and new additives will go through strict testing before they can be placed on the market. For most people, the chances of developing serious side effects (副作用) from the long-term use of presently approved (批准) food additives are very small.

    You're probably used to the regular upgrades in our cell-phone networks. There was 2G, which came along in 199l, replaced with 3G in 2001, followed by 4G in 2009. Now we're hearing about the coming of 5G.

    But 5G is a much bigger leap than before. 5G, of course, is much faster than 4G in the real world and a 5G phone in a 5G city will enjoy Internet speeds between 9 and 20 times as fast. The arrival of 5G also means enormous leaps forward in capacity－so much that every cell-phone plan will offer cheap, truly unlimited Internet access. "The consequences of that are huge," says Sherif Hanna, Qualcomm's director of 5G marketing. For example, apps will no longer degrade (降低) your video quality or postpone downloading when you're out of Wi-Fi range. In fact, you'll probably prefer to do your downloads when you're on cellular (使用流量) because 5G will be much faster than whatever service you've got at home or work.

    "However, not everyone is excited by the 5G development. The new standard gets its speed partly by using existing transmission(传输) frequencies more efficiently and partly by using the millimeter wave range. That's a big, juicy line of radio frequencies that are currently underused because millimeter wave is really hard to use," Hanna says.

    These frequencies are much higher than anything we've used for the cellular, which means they can offer unbelievable speed－but at the cost of range. Millimeter wave cellular towers have to be about 500 feet apart. Cell carriers not only will have to upgrade all their cell transceivers (called small cells) but will install(安装) a lot more of them as well.

    That's why the millimeter wave flavor of 5G, the superfast coverage, will be available only in densely populated cities such as New York and San Francisco. In suburban and rural areas, 5G will bring a speedup of "only" nine times faster.