Most people would say the sea is blue and green. But the people who live near the coast of Zhejiang may say it is red. It is not people who caused the colour change, but very small living thing in the sea. They are algae(藻类)and protozoa(原生动物). They come in many different colours; red, yellow or brown. Red is the easiest of those to see so when this happens people call it a “red tide.”

    Red tides only happen when conditions in the sea are right. In the past few years, factories and people have been putting more chemicals into the sea. These chemicals help algae and protozoa to grow very quickly. The temperature of the sea is also important. Red tides usually happen at 20 to 30 degrees Celsius. Red tides often happen in dry, warm areas where there is little wind. Living things grow easily in these places. Sometimes fishermen help red tides by mistake. They put small sea animals into the water for food to help fish grow.

    Those living things do more than change the colour of the water-they also put poison and mucus(黏液)into the sea. This is had for fish. The poison is bad for their brains. And too much mucus in the sea fills up fish's gills(鳃) so they can't breathe. Lots of dead fish and other sea animals are now washed up on Chinese beaches.

    Red tides can be bad for people too. We shouldn't eat fish from red-tide waters. The algae gets inside of fish and it smells bad. It can make your eyes water. If people eat fish with too much algae inside they could die.

    Fishermen in Zhejiang are having a hard time right now. Because of the red tide, they are selling 30% less fresh seafood than usual.

    In China red tides usually happen in May and June around places like Fujian Guangdong and Hong Kong.

    Many other countries sometimes also have red tides. But it seems that we have few ways to stop red tides. They can last as long as 16 months.

    It's pleased to receive gifts from your loved ones. I have received many Christmas gifts over the years. But the best gift I ever received was presented to me by a stranger. I never even knew his name and I only had contact with him for less than 60 seconds. His Christmas present to me changed the way I had thought about people and Christmas.

    It was several years ago when my wife asked me to meet her at the local department store on Black Friday morning. They had advertised a child's bike that she wanted to purchase for our son. We stood with a very large crowd, waiting for the manager to blow the whistle. After a while, the whistle blew. It was like throwing a bucket of fish into a tank of sharks. I told my wife that if we obtained a bike, fine, but if we did not, I was OK with that too.

    As the shelf of bikes began to gradually decrease in size, I saw my polite opportunity to wrap my hands around the corner of one of the boxes. I lifted it off the box and suddenly felt some mild resistance. I looked up to see one of the largest gentlemen I had ever seen in my life. Threat was not the word to describe his presence. He was decorated with numerous belts of metal pointed leather around both arms and even his neck. Tattoos (文身) were an obvious passion of his.

    I started to return anxiously the box but he gently pushed it back in my direction and back into my hands. He then directed it into my shopping cart. He looked at me, smiled, and said, “Merry Christmas.” My wife and I went to the checkout, paid for the bike and went home. All the way home I was thinking that this moment was by far the best Christmas gift I had ever received. The kindness of a stranger that broke all previous views I may have had of stereotypes and prejudices. I will never forget the tenderness of a human heart in a simple act.

    Sagrada Familia (2, 056, 448 visits/year)

    Opening hours: 09: 00-18: 00 (October-March)    09: 00-20: 00 (April-September).

    Admission: $11, or $10 with the Barcelona Card.

    Disabled access: Yes

    The temple has been under construction since 1882 and they've still got another 30 to 80 years to go before it will be finished. The project's vast scale (规模) and its special design have made it one of Barcelona's top tourist attractions for many years.

    La Pedrera (1, 133, 220 visits/year)

    Opening hours: 09: 00-18: 30 (November-February)    09: 00-20: 00 (March-October)

    Admission: $9. 50. Save 20% with the Barcelona Card.

    Disabled access: No.

    This building used to be called Casa Mila, but nowadays it's more commonly known as La Pedrera. It was made of bricks and had colorful tiles (瓷砖).

    Barcelona FC Museum (1, 032, 763 visits/year)

    Opening hours: 6th April-4th October: (Monday to Saturday) 10:00-20:00; the rest of the year: 10: 00 to 18: 30.

    Admission: $8. 50 for entry to museum and an extra $17 for a guided tour.

    Disabled access: Yes.

    It is now generally considered as the best football museum in the world. You can see so many trophies (奖杯), pictures and statues of great football players. I'm not a football fan but I still enjoyed walking round this museum.

    Miró Museum (518, 869 visits/year)

    Opening hours: Check website for details as they vary depending on the time of the year.

    Admission: $8. Save 20% with the Barcelona Card.

    Disabled access: Yes.

    This museum has a wide range of Miró's works dating back as far as 1914. This artwork collection includes not only his paintings but also a good selection of sculptures.

    When an earthquake hit a small town, many houses fell down. After the earthquake, all the newspapers reported many stories about some of the families who were in trouble.

    One Sunday, when I was reading a newspaper, a special picture touched me. It gave the clothing sizes of each family member. I thought that this would be a good chance to teach my children to help those who were less lucky than themselves. I said to my seven-year-old twins, Brad and Brett, and three-year-old Meghan, "We have so much, and these poor people now have nothing. We'll share what we have with them."

    I filled a box with foods and clothes. While I was doing this, I encouraged the boys to choose their toys and donate some of their less favorite things. Meghan watched quietly as the boys took out their old toys and games and put them together. Then she walked away. A few minutes later she came back with Lucy, her much-loved doll. She put the doll on top of the other toys. "Oh, dear," I said. "You don't have to give Lucy. You love her so much." Meghan said, "Lucy makes me happy, Mommy. Maybe she'll make another little girl happy, too."

    I looked at Meghan for a long moment. She taught me a lesson. It's easy to give something that we don't want any more, but hard to give what we cherish (珍爱), isn't it?

    At first, Michael Surrell didn't see the black smoke or flames shooting from the windows of his neighbors' home. He and his wife had just parked around the corner from their own house in Allentown, Pennsylvania, when they got a call from one of his daughters, "The house next door is on fire!" He went to investigate. That's when he saw two women and a girl hysterical (歇斯底里的)on their porch.

    "The baby's in there!" one of the women cried. Though the fire department had been called, Surrell, then 64, instinctively ran inside. "The baby" was 8-year-old Tiara Roberts, the woman's granddaughter and a playmate of Surrell's three youngest kids, then 8, 10, and 12. The other two on the porch were Tiara's aunt and cousin.

Entering the burning house was like "running into a bucket of black paint," Surrell says. The thick smoke caused him to stumble blindly around, burned his eyes, and made it impossible to breathe. The conditions would have been hazardous for anyone, but for Surrell, who has chronic obstructive pulmonary disease (慢性阻塞性肺疾病), they were life-threatening. He was the last person who should have run into a burning building— he has lung disease. But that didn't stop him.

    After a few minutes in the smoke filled house, he retreated outside to catch his breath. "Where is Tiara?" he asked desperately." The second floor." her aunt shouted back.

    Surrell knew he couldn't hold his breath for long. So he uttered a little prayer, "Well, Lord, this is it. You gotta help me, because I'm not coming out without that little girl." Taking a deep breath, he went in a second time.

    The darkness was overwhelming. Yet because the house had a similar layout to his, he found the stairs and made it to the second floor. He turned to the right and was met by intense heat. He was already out of breath.

    "Baby girl, where are you?" His throat and lungs burned as if he'd inhaled fire instead of the smoke and soot in the air. Every blink stung his eyes. All he could hear was the crackling and popping of burning wood. ①.Still unable to see, Surrell fell to his knees on the hot wood floor. He crawled toward the sound, feeling around for any sign of the girl. An ominous thought crossed his mind: I'm probably gonna die up here.

    Finally he touched something. A shoe, then an ankle. He pulled Tiara toward him. ②Her body was limp and she wasn't breathing. He scooped her into his arms and stood. He felt the heat of the flames on his cheeks. Turning, he fought through the smoke and ran blindly into the blackness. The next thing he knew, he was at the front door, then outside. Surrell put Tiara down on the porch.

    ③. A voice told him, "You have to breathe for her." He started CPR -the first time he'd ever done so. The women stood behind him, praying silently. Soon a soot-filled cough came from Tiara's throat. Surrell gave five more breaths. She coughed again. Her eyes flickered. He gave one final breath. She opened her eyes and took a breath on her own.

    ④.Their eyes met. Surrell hugged her tight and said, "Uncle's got you.^" Soon after, his throat closed off.

    Surrell woke up in the hospital a couple of days later, having suffered severe burns to his windpipe and the upper portion of his lungs. He spent over a week in the hospital. Tiara was released from the hospital after a few days. The fire exacerbated Surrell's pulmonary condition, and he feels the effects even two years later. As a result, he takes extra medication that helps open his airways. "It's a small price to pay," he says. "I'd do it again in a heartbeat. Wouldn't give it a second thought."

A key part of protecting endangered species is figuring out where they're living. Using environmental DNA, or eDNA, to track species isn't new. For a few years now, researchers have been using DNA in water.

Two teams of scientists — one in Denmark led by Dr Kristine Bohmann and one in the UK led by Dr Elizabeth Clare — came up with the same question at about the same time: Could they identify the animals in an area from DNA that was simply floating in the air? DNA in the air is usually so small that it would take a microscope to see it. "I thought the chances of collecting animal DNA from air would be slim though much time had been spent on it, but we moved on," said Bohmann who was trying to think of a crazy research idea for a Danish foundation that funds far-out science.

One team collected samples from different locations at Denmark's Copenhagen Zoo, and the other at Hamerton Zoo Park in the UK. Clearly, they both chose the zoos. "We realized we have the Copenhagen Zoo," Bohmann recalls. In fact, both the zoos in the UK and Denmark were almost like the zoos that were custom-built for the experiments: The animals in the zoos were non-native, so they really stuck out in DNA analyses. "If we detect a flamingo (火烈鸟), we're sure it's not coming from anywhere else but the zoo," Bohmann says.

In the laboratory, by comparing their samples with examples of DNA from different animals, the scientists succeeded in identifying many different animals at the zoos.

Neither team knew that the other team was working on a similar experiment. The two were nearing submission to a scientific journal when they discovered about the other experiment. Rather than compete to rush out a publication first, they got in touch and decided to publish their findings as a pair. "We both thought the papers are stronger together," says Clare.

"The next step is to figure out how to take this method into nature to track animals that are hard to spot, including endangered animals," says Bohmann.