If you are riding a bike in foreign countries, you need to know what these traffic signs mean.

1		This sign means “walk”, you can cross the street along with other people.
2		This sign is the “don't walk” sign. It means you should stop to wait for a while until the sign of “walk” is showing.
3		This sign means that there is a bike lane. If you see such a sign, you must use the bike lane.
4		Car drivers and bike riders must come to a complete stop at “STOP” signs.
5		This sign means you are coming to a zebra crossing. You must slow down to allow people in the zebra crossing to cross the street.
6		This sign means parts of the road are rough. Be careful! Rough roads make you fall off your bike.

C

    Almost all cultures celebrate the end of one year and the beginning of another in some way. Different cultures celebrate the beginning of a new year in different ways, and at different times on the calendar(日历).

    In Western countries, people usually celebrate New Year at midnight on December 31st—January 1st. People may go to parties, sometimes dressed in formal(正式的) clothes, and they may drink champagne(香槟酒)at midnight. During the first minutes of the new year, people cheer and wish each other happiness for the year ahead. But some cultures prefer to celebrate the new year by waking up early to watch the sunrise. They welcome the new year with the first light of the sunrise.

    Many cultures also do special things to get rid of(摆脱) bad luck at the beginning of a new year. For example, in Ecuador(厄瓜多尔), families make a big doll from old clothes. The doll is filled with old newspapers and firecrackers. At midnight, these dolls are burned(燃烧) to show the bad things from the past year are gone and the new year can start afresh(重新). Other common traditions to keep away bad luck in a new year include throwing things into rivers or the ocean, or saying special things on the first day of the new year.

    Other New Year traditions are followed to bring good luck in the new year. One widespread(普遍的) Spanish tradition for good luck is to eat grapes on New Year's Day. The more grapes a person eats, the more good luck the person will have in the year. In France, people eat pancakes for good luck at New Year. In the United States, some people eat black­ eyed peas(豌豆) for good luck—but to get good luck for a whole year you have to eat 365 of them!

    A new App has been used in South Africa to benefit (有助于)the relationship between wildlife and humans.

    Roadwatch, created by the Endangered Wildlife Trust (EWT),is designed to let drivers   record any roadkill they see on the country's highways.

    It may seem like a strange idea, but EWT says that it could become the perfect platform for receiving important information. Information on where endangered species (物种）are living and the danger that they are under from traffic can help to inform decisions on conservation of matters (物质守恒）in the future.

    People can use the App through Facebook, WhatsApp, SMS and Linkedin to report the   species, location, time and date of the creature that has been seen on the road.

    Wendy Collinson field officer at EWT suggested that it could lead to more people taking care on the roads and paying more attention to animals that may be trying to cross the roads. One of the biggest problems is with reptiles (爬行动物）and snakes, which she believes people hit on purpose, as they are generally seen as scary. However, they are important to the health of ecosystems, just as all creatures are and also need to be protected.

    Emily Taylor from EWT said, “Roadkill simply hasn't been studied here. The road ecology and how many endangered species are being killed, is something we need to know more about. We want people to report as much as possible.”

    There have been some other Apps to use in relation to wildlife spotting in South Africa, but most of them are about animals that have not been knocked down, including those helping to collect information of where certain species have been seen, such as in parks.

    What is the best way to help control air pollution in our towns and cities? Choose public transportation instead of private cars, or reduce the total amount of cars on the street. These can be useful. But here is a more creative way—write a poem.

    "I write in praise of air. I was six or five, when a magician opened my fist(拳头), and I held in my hand the whole of the sky."

    Professor Tony Ryan (the science expert) and Professor Simon Armitage(the words expert), from the University of Sheffield, UK, came up with the idea.

    But in fact, the poem is not the key part. It is the poster that the poem was written on that plays the biggest part. The poster is 10 meters by 20 meters. It is coated with nanoparticles(纳米粒) of titanium dioxide (二氧化钛). It can absorb the waste from around 20 cars each day if you put it by a busy road. The poster is now displayed on one of the University of Sheffield's buildings.

    It doesn't get rid of all the pollutants from traffic, but it will eat up things called nitrogen oxides (氧化氮). These play a part in breathing problems, including asthma(哮喘).

    The technology is cheap. "It would add less than £100 to the cost of a poster and would turn advertisements into catalysts(催化剂) in more ways than one," Ryan told the BBC.

    He's also working on another idea, which is to add the nanoparticles to washing powder, so that your clothes soak up these poisons while you walk along. And you wouldn't be able to see or feel anything different.

    Is there intelligent (有智力的) life on other planets? For years, scientists said "no" or "we don't know". But today this is changing. Seth Shostak and Alexandra Barnett are astronomers (天文学家). They believe intelligent life exists (存在) somewhere in the universe. They also think we will soon contact these beings (人；生物).

    Why do Shostak and Barnett think intelligent life exists on other planets? The first reason is time. Scientists believe the universe is about 12 billion years old. "This is long enough for other planets to have intelligent life," say Shostak and Barnett. The second reason is size—the universe is huge. "Tools like the Hubble Telescope (哈勃望远镜) have shown that there are at least 100 billion galaxies," says Shostak. "And our galaxy, the Milky Way, has at least 100 billion stars. Some planets going around these stars might be similar to Earth."

    In the past, it was hard to look for signs of intelligent life in the universe. But now, powerful telescopes (高倍望远镜) allow scientists to discover smaller planets. These planets might have intelligent life.

    Have beings from space already visited Earth? "Probably not," says Shostak. However, intelligent beings may contact us in other way, such as radio signals (信号). In fact, they may be trying to communicate with us now, but we don't have the right tools to receive their messages. However, this is changing. By 2025, we could make contact with other life forms in our universe and we might help each other.