Animals can move from place to place, but plants cannot. When an animal is under attack, it can run away or fight back. Plants certainly cannot run away, and they have no teeth or claws. But plants can protect themselves in both physical and chemical ways.

    Some plants have their own ways to keep animals away. For example, the leaves of the holly(冬青) have sharp prickles(刺) that discourage grass-eating animals. Holly leaves on lower places have more prickles than leaves on upper places. This is because the lower leaves are easier for most animals to reach. Some plants, such as the oak trees(橡树), have thick and hard leaves that are difficult for animals to eat. Some grasses may contain a sandy material, and eating such grasses wears down the animals' teeth. Many plants also have chemical defenses. Some plants produce chemicals that taste bitter(苦) or cause an unpleasant reaction. Some plants may fight against an attack by increasing the production of these chemicals. When a worm bites a tobacco leaf (烟叶), the leaf produces a chemical smell. Many plants depend on both physical and chemical defenses. A certain plant in China, for instance, has prickly leaves, and each prickle has poisonous water(毒液). Only one experience with this kind of plant will teach an animal to stay away from it in the future.

    The evening of September 29, 2011, China launched (发射) its first space lab module Tiangong-1 at the Jiuquan Satellite Launch Center in northwestern China.

    President Hu Jintao praised the success of China's first space lab module Tiangong-1, and shook hands with the staff of the Beijing Aerospace Flight Control Center.

    Premier Wen Jiabao and He Guoqiang also shook hands with the staff at the Jiuquan Satellite Launch Center to congratulate on the success.

    Tiangong-1, which is plannedtoconnect with the Shenzhou-8 spacecraft later this year, will get ready for building China's first space station.

    During its two-year service life, Tiangong-1 will mainly carry on four tasks, such as experiments of autonomous rendezvous(自主交会) and connection with the Shenzhou-8, -9, and -10 spacecrafts in the coming launches, which is going to set up the country's first space lab, according to Wu Ping, spokesperson for China's National Space Administration.

    According to the plan for China's manned space program, the Shenzhou-10 will be a manned spacecraft that is going to carry a female Chinese astronaut.

    Tiangong-1 is expected to become China's first space laboratory when it connects to the above mentioned spaceships.

    Rainforests (热带雨林) cover six percent of the earth's surface (表面). There are rainforests in many parts of the world. About 75 percent of animals live in rainforests. There are many beautiful birds, insects and so on. Some of them live on the ground, some live under the ground and others live in the trees, over 30 meters from the ground. It is always hot in the rainforests and the ground is always wet. It is also very dark there.

    The rainforests are very important for us. We need them! The trees and other plants in the forest help to make the air clean. They also help to control (控制) the temperature.

    Unfortunately, in many places, the rainforests are in danger. For example, many years ago there was a large rainforest in Java, but now there is nothing. The same thing happens now in many other parts of the world. It's time to take action to save the rainforests. We can never imagine a world without rainforests. If rainforests disappeared from the earth, we wouldn't find any trees, flowers or fruits. What's more, we wouldn't get clean air, and we wouldn't find any animals. The worst result would be that we wouldn't find any humans.

    Tablets are really useful devices, but their big screens always make them as a burden to carry around without a bag. Wouldn't it be great if there were a phone with the powers of a tablet that could be folded up and fit into the hand?

Now something like a tablet-shaped but foldable phone is about to become available. In February, South Korean electronics company Samsung and China's Huawei both showed foldable phones, The Galaxy Fold and Huawei Mate X respectively. Mobile phone use has entered the "foldable future", The Verge noted.

    The technology could change our lives in unusual ways. These devices, due to their foldable screens, give us the larger screens we want. At the same time, they still fit easily into the pocket. As USA Today noted, they're "the combination of a small tablet and smartphone, all in a single device".

    The technology could change other devices too. For example, we could make TVs that stick to walls like posters, or fold up easily to hide away in drawers. In crowded modern cities, they will help us to make full use of available space.

    In a keynote speech, Samsung's senior vice president of mobile product marketing, Justin Denison, called the foldable screen "the foundation for the smartphone of tomorrow". "It's a piece of white paper for us to paint something beautiful on together," he said.

    So is there nothing to stand in the way of the foldable future?

According to technology news website Android Authority, the necessary displays* were difficult to produce. At present, these foldable devices cost too much. For example, the price of Huawei Mate X is 17,500 RMB. That's a price that few people will be able to afford.

    But if the foldable device isn't going to change the world overnight, there is no doubt that it is coming.

    Patrick Moorhead, an industry expert told The Verge, "Few are debating if foldable mobile displays are the future of smartphones; the only question is when and by whom."

    Populations of white-tailed deer(白尾鹿) are growing rapidly in many parts of the United States. As populations grow, food becomes a problem. Many deer die of hunger. Others grow up small and unhealthy. In search of food, hungry deer move closer to where humans live. They eat farm crops, vegetables and even trees. Besides, increased numbers of deer near roads can cause traffic accidents.

    People admire the grace and fast speed of deer. Most people don't want these animals to be hungry and ill. Should people take action to control the growing deer populations?

Should People Take Direct Action?

    Many people think that hunting(打猎) is the best way to control the animal populations. Wildlife managers will see if there's enough food in an area and decide its carrying capacity(容量). Then hunters with licenses are sent to help control the number of deer. Hunting is usually not allowed in cities or suburbs, however.

    Some people have the idea to catch the deer and move them to other places. But this method is expensive and requires finding another place that can accept the deer without breaking the balance of ecosystem(生态系统).

    Scientists are also working to develop chemicals(化学药品) to control the birth rate(率) in deer populations. But this plan works for only one year at a time.

Should People Take Indirect Action?

    Some suggest bringing in natural enemies of deer, such as wolves, lions and bears, to areas with too many deer. But these animals could also hurt dogs, cats, and even humans. Other communities have built tall fences(篱笆) around areas to keep out the deer. However, this is impossible for farmers.

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    Some people are against any kind of action. They support leaving the deer alone. Animal populations in an area naturally go up and down over time. Doing nothing means that some deer will die of hunger or illness. But finally, the population will reach a size within the carrying capacity(容量) of the environment. So, let nature go its own way.