Coffee and tea are two of the most popular drinks in the world. However, people usually like one more than the other. These drinks also have very different uses.

Coffee started just over 1,000 years ago. Coffee is made from beans. Something in the coffee beans makes a person feel active. Most people do not drink coffee to relax.Instead, they drink coffee to get going. Many people drink coffee in the morning to help them wake up. Others will also drink coffee during short breaks in the afternoon to keep going through the working day. Some people may visit coffee shops just to meet and talk with friends. However, many people in coffee shops drink coffee while working on their computers.

People in China started to drink tea over 4000 years ago.Tea is made from leaves. These days, some people drink tea for health,using it to help with stress or losing weight*. However most people in tea-drinking countries think tea is more than a healthy drink. In fact, tea drinking in some countries is part of the culture. In Turkey, tea is always there when people meet. Whether in someone’s home or a company, tea is always offered as a way of welcoming. In the UK, homes and offices usually have tea time. Tea and other dishes are served at tea time in the afternoon. It is a way of relaxing with friends or co-workers.

Which is more common in your country, coffee or tea? Which do you like to drink more?

Little birds talk with their sisters and brothers in their nest. They make a sound for food. Mum tells them to be quiet when danger（危险） comes. But now a new study finds: that kind of talk starts long before the babies are born. Even in the eggs, they can talk with each other and know when to get out or when to keep waiting.

To check that finding, a team of scientists from Spain watched unborn birds carefully in Salvora Island. Over there, sea birds have their eggs and minks（水貂） eat baby birds. So it is quite a dangerous place for baby birds. Knowing when to come out of the egg is important for baby birds to start their new life.

Scientists got some sea bird eggs and put them into two groups. When minks come, a parent bird will give calls to tell the baby birds that danger is coming. Scientists played those calls for one group. The other group stayed in another box and they would never hear such calls.

When scientists put all the eggs together, they found something surprising: after hearing those calls, the eggs vibrated（震动；抖动） more than the others. Those vibrations moved from one egg to another. It was just like there were ears in the eggs. It was clear that unborn birds talked with their sisters and brothers about danger.

①Being an astronaut sounds cool, doesn’t it? In space, they get to do some pretty amazing things, like floating（飘移）in zero gravity.

②However, there are also plenty of things that astronauts can’t do because of zero gravity. They can’t even let their sadness show—because it’s impossible to cry in the weightless environment.

③Of course, astronauts can still produce tears. But crying is much more difficult in space, reported The Atlantic in January. Without gravity, tears don’t flow（流）downward out of the eyes like they do here on Earth. This means that when you cry in space, your tears have nowhere to go—they just stick to your eyes. In May 2011, astronaut Andrew Feustel experienced this during one of his spacewalks. “Tears,” he said, “don’t fall off your eye... They just kind of stay there.”

④Besides making your vision（视线）unclear, this can also make your eyes painful. Back on Earth, tears are supposed to bring comfort to the eyes. But that’s not the case in space. The space environment dries out astronauts’ eyes, and when tears suddenly wet the eyes, it can cause pain rather than comfort. “My right eye is hurt,” Feustel told his teammate during the walk.

⑤Since gravity doesn’t work in space, astronauts need some extra help to get rid of the tears. Feustel chose to rub his eyes against his helmet（头盔）to wipe the tears away. Another choice is to just wait “When the tears get big enough they simply break free of the eye and float around,” astronaut Ron Parise told The Atlantic.

⑥There are lots of small things—things like crying—that we are so used to on Earth. There, astronauts can’t eat or drink in normal ways. They can’t even burp（打嗝）, because there is no gravity to hold the food down in their stomach.

⑦Perhaps it’s only space explorers who can honestly say, “Gravity, you’re the best.”