There have been claims that warming on Mars(火星) and Pluto(冥王星) is proof that the recent warming on Earth is caused by an increase in solar activity, and not by greenhouse gases. But we can say with certainty that, even if Mars, Pluto or any other planet has warmed in recent years, it is not due to changes in solar activity.

The Sun’s energy output has not increased since direct measurements began in 1978. If increased solar output really was responsible, we should be seeing warming on all the planets and their moons, not just Mars and Pluto.

    Our solar system has eight planets, three dwarf planets and quite a few moons with at least a thin atmosphere, and thus a climate of sorts. Their climates will be affected by local factors such as orbital variations, changes in reflectance and even volcanic eruptions, so it would not be surprising if several planets and moons turn out to be warming at any one time.

    One theory is that winds have recently swept some areas of Mars clean of dust, darkening the surface, warming the Red Planet and leading to further increases in windiness --- a positive feedback effect.

Observations of the thickness of Pluto’s atmosphere in 2002 suggested the dwarf planet was warming even as its orbit took it further from the Sun. The finding confused astronomers at the time, and the cause had yet to be determined.

It has since been suggested that this is due to a greenhouse effect: As it gets closer to the Sun, Pluto may warm enough for some of the methane ice on its surface to turn into a gas. This would cause further warming, which would continue for a while even after Pluto’s orbit starts to take it away from the Sun.

With its incredibly long neck, giraffe looks like no other animal on Earth. But how did this mammal come to get its famously huge neck? Well, scientists have been asking themselves this question for centuries.

The most commonly believed answer is that the massive neck – which measures on average 180 centimeters and weighs about 270 kilograms – evolved to allow the animal to reach the leaves of tall trees. British scientist Charles Darwin was one of the first people to propose this idea in the 1800s.

Yet, there are other theories.

According to a paper published in September in the Journal of Arid Environments, the giraffe’s neck evolved to increase its surface-area-to-volume ratio (表面积—体积比). Because the animal’s neck increases its body’s surface area, it makes it easier for it to keep cool, the paper’s authors wrote.

This phenomenon can be seen everywhere in nature. For example, this is why elephants have such large ears.

Meanwhile, some believe that competition is the answer.

A 1996 study by two South African zoologists argued that the male giraffes with the biggest necks are the ones who “win” access to females to reproduce, as they are better at fighting, meaning that their long necks are passed down through the generations.

So, it seems like there’s still no definite answer to the question.

Shoppers could soon use their mobile phones to check how ripe fruit and vegetables are with an “X－ray vision” camera.

    The HyperCam, based on hyper spectral (高光谱的)imaging, can assess ripeness with 94 percent accuracy and could also be used to check for rotting produce in the fridge at home. Scientists at the University of Washington in Seattle managed to create a portable hyper spectral imaging camera that would cost $ 800 (£520).

     Hyper spectral imaging uses a broader range of the electromagnetic spectrum(电磁波)than an ordinary camera. The researchers are now working on a version of the technology that shoppers could download on to a mobile phone for about $ 50. The technology is already used in satellite imaging, building safety inspection, but is a highly costly process.

    Professor Shwetak Patel, of the University of Washington, said: “It’s not there yet but you can probably imagine putting it in a mobile phone. With this kind of camera you could go to the grocery store and know what produce to pick by looking underneath the skin and seeing if there’s anything wrong inside. It’s like having a food safety app in your pocket.”

    Neel Joshi, a Microsoft researcher, said: “Existing systems are costly and hard to use so we decided to create an inexpensive hyper spectral camera and explore these uses ourselves. After building the camera we just started pointing it at everyday objects, really anything we could find in our homes and offices, and we were amazed at all the hidden information it revealed.”

    Other potential uses for the technology include analyzing blood vessels and identifying individual people by the unique texture (纹理) of their skin.

Vancouver is located in the southwest corner of Canada in the province of British Columbia. Vancouver is the largest city in the province and the third largest in Canada. It covers an area of 113 sq km. It is surrounded by water on three sides and overlooked by the Coast Range. Its climate is one of the mildest in Canada. Temperatures average 3°C in January and 18°C in July. Vancouver's most rainfall occurs in winter.

       Archaeological evidence shows that coastal Indians had settled the Vancouver area by 500 BC. British naval captain George Vancouver explored the area in 1792. Vancouver was founded as a sawmill settlement called Granville in the 1870s. The city was united in 1886 and renamed after Captain Vancouver.

       As the main western terminus of Canada's transcontinental highway and rail routes, Vancouver is the primary city of western Canada, as well as one of the nation's largest industrial centres.

       The Port of Vancouver is Canada’s largest and most various port, trading more than $43 billion in goods with more than 90 trading economies annually. Port activities generate 69,200 jobs in total with $4 billion in gross domestic product (GDP) and $8.9 billion in economic output.

       Vancouver is a major tourist place. In addition to the city's scenic location, visitors enjoy beautiful gardens and world-famous Stanley Park, one of more than 180 city parks, and a combination of natural forest and parklands near the city centre.

The world itself is becoming much smaller by using modern traffic and modern communication means. Life today is much easier than it was hundreds of years ago, but it has brought new problems. One of the biggest problems is pollution. To pollute means to make things dirty. Pollution comes in many ways. We see it, smell it, drink it and even hear it.

Man has been polluting the earth. The more people, the more pollution. Many years ago, the problem was not so serious because there were not so many people. When the land was used up or the river was dirty in one place, man moved to another place. But this is no longer true.

Man is now slowly polluting the whole world.

Air pollution is still the most serious. It’s bad for all living things in the world, but it is not the only one kind of pollution. Water pollution kills our fish and pollutes our drinking water. Noise pollution makes us angry more easily.

Many countries are making rules to fight pollution. They stop people from burning coal in houses and factories in the city, and from putting dirty smoke into the air. Pollution by SO₂ is now the most dangerous kind of air pollution. It is caused by heavy traffic. We are sure that if there are fewer people driving, there will be less air pollution.

The earth is our home. We must take care of it. That means keeping the land, water and air clean. And we must take care of the rise in pollution at the same time.

D

The sun is setting on a summer night. At the entrance to a deep, dark cave, a few bats fly out. Then more and more of the small, furry creatures appear. Within a few minutes, a whole river of bats is pouring out of the cave, and they keep coming — millions and millions of them.

       Sound like a scary horror movie? Believe it or not, this scene takes place every night, all summer long, at Bracken Cave in Texas, where 20 million bats fly outside to feed on insects.

      Every March or April, Mexican free-tailed bats migrate up to 1,609 kilometers from their winter home places, like mines, tunnels, hollow trees, and under bridges in Mexico to this cave. Soon after they arrive, each mother gives birth to one baby bat. As many as 500 baby bats live crammed (挤) into one square foot of space, and those bodies create nice warm temperatures to keep them warm and comfortable. With bad sight, how can mother bats recognize their own babies? Their good sense of smell helps them the most.

      When the adult bats leave the cave at night to feed, they eat tons of insects in a single night, including many pests that eat farmers’ crops. And they get rid of mosquitoes, too.

      The cave, quiet in winter, is full of life all summer. The floor of the cave is covered with bugs. Gnats are flying around, and beetles are crawling up your leg when you walk in!

      When twenty million bats fly out of one cave opening, they make a column (柱) so thick that they show up on the radar at the nearby airport. So much for bats being scary!

B

  Iceland is a large island．In fact，it’s the world’s 18th largest island．Most of the population，however，lives in the southern part of the country，in or around the capital city of Reykjavik．By its very name，you’d expect Iceland to be mostly ice．Looking at Iceland on a map，you’ll notice it sits just outside the Arctic Circle．Despite this location and its name，Iceland actually has temperate climate because it’s warmed by the Gulf Stream．The Gulf Stream also helps keep Iceland’s coastal ports ice—free through the winter．

  There is plenty of ice on Iceland，though．The country consists of a large plateau(高原) that includes fields of sand，mountains and glaciers(冰川)．Over sixty percent of Iceland is tundra(苔原)．About fourteen percent of Iceland is lakes and glaciers．Only about twenty—three percent of the country has plants or vegetation of any kind．

  Iceland was settled in the late 800s and early 900s by Norsemen from the Scandinavian country of Nmway．Other settlers also came from Ireland and Scotland．From the thirteenth century up until 1918，Iceland was part of the Norwegian and later Danish monarchies．For most of that time，the small Icelandic population depended upon fishing and farming to make a living．For hundreds of years，Iceland was one of the poorest and least developed countries in the world．After World War Ⅱ，international aid and industrialization of the fishing industry turned Iceland into one of the wealthiest countries in the world．In 1914，Iceland became part of the European Economic Area，which allowed its economly to grow even more．

  Iceland is one of the youngest islands in the world．Surtsey rose out of the ocean during a series of volcanic eruptions between 1963 and 1968．Today，only scientists who study the growth of new life can visit the volcanic island of Surtsey．

C

     Bali is a tiny island that is part of Indonesia(印度尼西亚) today. It is a pretty island that has many mountains and a pleasant climate. For a long time, Bali was cut off from much of the world.

The people of Bali were happy and had a peaceful life. They were not allowed to fight. At one time there had been terrible wars on Bali. Then the people decided it was wrong to fight or have wars. They made rules to keep apart those people who wanted to fight.

Bali was divided into seven small kingdoms. The land around each kingdom was kept empty, and no one lived there. Since the kingdoms did not share the same borders(边界), the people could not fight about them.

On Bali, even children were not allowed to fight. If two children started a fight over a toy, someone separated them. When two boys argued, they would agree not to speak to each other. Sometimes they did not talk together for months; this gave the boys a chance to forget their anger.

Families who were angry with each other also promised not to speak. Their promise was written down, and the whole village knew about it. If they broke their promise, they had to offer gifts to their gods.