Want to stay away from colds? Put on a happy face.

Compared to (与……相比) unhappy people, those who are cheerful and relaxed are less likely to suffer from colds, according to a new study. It’s possible that being happy helps the body fight illnesses, say the researchers from New York University.

“It seems that positive (积极的) feelings may reduce the danger of illness,” said the study’s chief researcher Sheldon Cohen.

In an earlier study, Cohen found that people who were cheerful and lively caught coughs and colds less often. People who showed positive feelings were also less likely to tell their doctors that they felt ill.

In this study, Cohen’s team interviewed 193 adults every day for two weeks. During the interviews, the people told researchers about the happy or sad feelings they had that day. After the two weeks, the people were given colds by doctors and had to stay alone in a room for six days.

Cohen believes that when people experience positive feelings, their body may produce a chemical that helps fight illness and disease. So if you are worried about your health, look on the bright side more often.

Ants (蚂蚁) are kind of like humans, because they live in big “ant cities”. In the ant cities, thousands of ants work together to build homes, find food and so on. Each ant city has a queen, and she mainly lays (产) eggs. In these ant cities, there are special rooms for keeping food and taking care of baby ants. Some ants have to pick up all the rubbish from the city and bring it outside the city. Do you think all that rubbish might be too much for a little ant? Even though they are so small, ants can carry some heavy things.

The door to their underground world is what we call an “anthill (蚁丘)”. The anthill is made up of sand and dirt. In the middle is a little hole through which the ants can climb down into their underground city. Imagine trying to organize such a thing! You’d think that ants must be very good communicators.

The interesting part about ants is that they can’t talk. But this doesn’t stop these little animals. Ants communicate by sending out different chemicals (化学物质) from their bodies for other ants to smell. For example, if an ant finds a piece of food, it will send out a kind of chemical that says “there is food here”. The other ants will follow their noses toward the food until it is all gone. If there is something perilous around, ants will send out a kind of chemical that says “stay away”. Each city of ants has its own special smell. This way ants can tell if there is danger.

So next time you see ants, stop and think about how amazing these little animals are and what their lives are like.

The idea of life in outer space has been talked about for a long time. Some scientists say that life development on Earth was far too unlikely for it to have happened anywhere else. Things had to be perfect for us to make it on this planet.

Other scientists say that space is too big. Stars and other planets are far too numerous for there to be no other life in the universe.

For many years, there have been reports of visitors from other planets. People all around the world have claimed to see alien spaceships or even aliens themselves.

There have been glimpses of these so-called UFOs (unidentified flying objects) flying through the air and they have even ben captured on video. Some Americans believe that the U.S. Army found an alien spaceship erashed in the desert and then lied to the press about it. Although these sightings may be true, scientists have not found significant evidence that aliens exist.

If you go out into the countryside on a clear night and look up, you can see thousands of stars. Those stars make up a tiny part of our universe. There are more stars, planets, and galaxies than we can count. Even the smartest scientists can't even come close to defining how big space is. The number of possible stars and planets out there is bigger than our ability to count. If we are really on the only planet that can sustain life, then we are very specinl in a universe full of amazing things.