While watching movies, it's getting hard to tell what is and isn't real. Thanks to computers, movie makers can now use their full imaginations. There's even a new type of character--made entirely by computers—which is getting more and more screen time.
    Making the impossible look easy has always been a part of movie magic. As far back as 1895, filmmakers used special effects in movies. Over the years, many few techniques（技术） were developed. Then, starting in the 1970s, computers took their place at the center of the process.
    One of the first movies to widely use 3D computer generated（生成的，产生的） imagery (CGI) was Tron(1982). In the following years, more CGI characters were brought to life, one by one. Then, Jurassic park (1993) brought us an island full of man-eating dinosaurs. Shortly afterwards, Toy Story (1995) became the first cartoon made entirely with 3D CGI effects. It was a big hit, and audiences loved the characters.
    By using “motion capture” technology, filmmakers can make the movements of CGI humans even more lifelike. With this technique, a real actor wears sensors（感受器，传感器） on his face and body. The sensors record the actor's movements and send the information to a computer. Then the movements are given to a CGI character. This technique was used to make the creature（生物，有生命的东西） Gollum in the second and third The Lord of the Rings movies (2002, 2003). Other films, like Beowulf (2007), have also used motion capture to help create CGI humans.
    It is still rather easy to tell that a CGI human is not real. But the technology is improving every year. Over time, many problems ( like the teeth and eyes looking fake) will be solved. We will certainly see more CGI animals, monsters, and people in movies and TV shows. The question is – in the future, how many real actors will be put out of work by computer actors?

    Is there intelligent(有智力的) life on other planets(行星)? 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 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 (银河系) ," 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--the size of Mars or Earth--in other solar systems (太阳系).These planets might have intelligent life.

    Have beings from space already visited Earth? "Probably not," says Shostak. "It's a long way away. 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.

    One day, you open the fridge and find some moldy (发霉的)food. But before you can throw it away, your mother stops you. She doesn't want to waste food. She cuts off the moldy part and eats the rest. Is it safe to do this?

    Mold (霉菌)can grow on almost all kinds of food. Mold is usually green, white, black or grey. Mold makes food soft and changes its color. Moldy food tastes quite bad一一and it's not safe to eat.

    If you find mold in soft food, just throw it away. Soft food, such as bread, tomatoes or hot dogs, usually contains water. This allows mold to easily grow below its surface. Bacteria (细菌)can also grow along with it.

    But it's easy to remove mold from hard food. The mold can't grow very deeply inside this kind of food. According to the BBC, you should cut about 2.5 cm around and below the mold to remove it. It's OK to cut the moldy parts out of hard food and eat the rest. But if the food is completely covered with mold, you should still throw it away.

    Most kinds of mold are bad for us. But some kinds of mold can be used to make food. For example, penicillium (青霉菌)can be used to make many types of cheeses, such as blue cheese. These cheeses are safe to eat--and they're quite delicious as well.

    A long time ago, people thought that the Sun went round the Earth. In some countries people even said that the Sun was a god (神). They thought the god drove across the sky each day on a golden horse. Now we know the Earth goes round the Sun. It takes the Earth a year to go all way round the Sun. Today men even know how far it is for the Earth to go round the Sun. They tell us that the Earth travels over a thousand miles a minute on its journey round the Sun.

    The Sun is really a star. It is much bigger than the Earth and it is very hot. Some people have been to the Moon but we know that no one can ever go to the Sun. It is far too hot for people to live anywhere near it. The Sun is about three hundred thousand times heavier than the Earth and more than a million times larger.

    Many people like to travel by plane, but I don't like it because an airport is usually far from the city. You have to get there early and wait for hours for the plane to take off and it is often late. You can't open the window. You can't choose the food. Planes are fast, but it still takes hours to get out of the airport and into the city.

    I like traveling by train. I think trains are safe. Railway stations are usually in cities. When you are late for a train, you can catch another one. You can walk around in the train and open the windows. You can see many interesting things on your way. I know it takes a little more time.

    I also like cars. You can start your journey when you want to, and you don't need to get to a railway station or a bus stop. Also you can take many things with you in a car. But sometimes there are too many cars on the road.