Scientists are debating how to limit their newly-discovered power to change genetic structure (结构). Scientists already modify the genes (基因) of farm animals and agricultural plants to make them more productive or stronger. But now they can also change genes in wild animals and plants. These genes would continue into later generations. For example, it may be possible for scientists to remove from existence the kind of mosquitoes, small flying insects, that carry the Zika virus. They might also be able to permanently remove species (物种) of plants and animals that are damaging to other species.

    In a report published last week, the U. S. National Academies of Sciences, Engineering and Medicine (NAS) said it supports continued research on this kind of gene control. But it warned that it is not possible to know what will happen when these changed plants and animals are released (释放) into the wild.

    Sixteen biologists, ethicists (伦理学家) and policymakers are on an NAS committee that is examining the issue. They say that there is value to the new technology. But, they say, there is not enough evidence to support the release of modified organisms (生物体) from the laboratory into nature.

    Many people would support stopping mosquitoes and rats from carrying diseases. But scientists say we must understand the possible scientific, ethical, legal and social results of such action before we decide whether to take it. Gene modification is spread through reproduction (繁殖).

    Changed genes will continue to spread as long as an animal or plant continues to reproduce. They cannot be limited to a farm or kept within a country's borders. Scientists are wondering what may happen if a modified organism mates with another species. They are not yet sure how the modified genes would affect the other species. It is possible that those genes could harm those creatures or even lead to their disappearance from our planet.

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    Languages have been coming and going for thousands of years, but in recent times there has been less coming and a lot more going. When the world was still populated by hunter-gatherers, small, tightly knit(联系) groups developed their own patterns of speech independent of each other. Some language experts believe that 10,000 years ago, when the world had just five to ten million people, they spoke perhaps 12,000 languages between them.   

    Soon afterwards, many of those people started settling down to become farmers, and their languages too became more settled and fewer in number. In recent centuries, trade, industrialisation, the development of the nation-state and the spread of universal compulsory education, especially globalisation and better communications in the past few decades, all have caused many languages to disappear, and dominant languages such as English, Spanish and Chinese are increasingly taking over.

    At present, the world has about 6,800 languages. The distribution of these languages is hugely uneven. The general rule is that mild zones have relatively few languages, often spoken by many people, while hot, wet zones have lots, often spoken by small numbers. Europe has only around 200 languages; the Americas about 1,000; Africa 2,400; and Asia and the Pacific perhaps 3,200, of which Papua New Guinea alone accounts for well over 800. The median number （中位数）of speakers is a mere 6,000, which means that half the world's languages are spoken by fewer people than that.

   Already well over 400 of the total of 6,800 languages are close to extinction (消亡), with only a few elderly speakers left. Pick, at random, Busuu in Cameroon (eight remaining speakers), Chiapaneco in Mexico (150), Lipan Apache in the United States (two or three) or Wadjigu in Australia (one, with a question-mark): none of these seems to have much chance of survival.

    When we have troubles we turn to our family. But what would we do if we lost our family? I want to share with you a touching film about an Indian child who loses his loved ones.

    The main character in the 2016 Australian film Lion is a child named Saroo. When he is 6 years old, he follows his brother Guddu to a job, but gets lost. Saroo ends up in a new city and is adopted by a kind Australian family.

    However, one day Saroo is reminded of his original family. He knows immediately that he must find out as much about them as he can, so he racks his brains (绞尽脑汁)for all that he can remember.

    Lion is the most moving film that I have ever seen. When I saw the young Saroo trying to help his brother while they worked on a construction site at such a young age, I was amazed.

    In today's society，the poor are always looked down upon. But I saw in the eyes of young Saroo great courage and kindness that made me think differently. He has great qualities that help him survive in the strange city where he finds himself.

    When Saroo sees that people are kind he rewards them with the sweetest smiles and loves them with all of his heart. Saroo's goodness, I believe, allows him to live a happy life with his Australian foster (收养)family.

    It is unbelievably hard for Saroo to reunite with his original family. He can't even remember the name of his hometown. It takes him days to find the real one. In fact, he has to go through every alternative (供选择的东西)he can find on Google Maps.

I'm deeply impressed by Saroo's determination. It is why, when I saw the movie, I cried at the moment when he finally found his mother.

    Lion is full of moving and impressive details. There are so many that I can only mention a few of them here. But what stands out most to me is Saroo's commitment (投身)to finding his original family，and the fact that his search doesn't stop him from loving his foster family.

    I want to recommend this film to everyone. See it and you'll come to understand so much about family and love.

    I've been really lucky this year. Not only did I have the opportunity to live in France, but I was able to see some other countries with my girlfriend. Now she is studying in Essen, a large city in Western Germany. I recently went to stay with her—it was my first visit to Germany! Essen is a very large city. It has all the conveniences of any large city so I felt immediately at home. I loved the variety of shops, restaurants, shopping malls, cocktail bars, nightclubs, parks and even a lake. There is also a city­wide network of trams, which makes getting around a piece of cake!

    I found the people to be really friendly, and most Germans speak very good English which made life easy for me. I was surprised by the casual attitude to alcohol in Germany, where it seems normal for people to drink beer on the street, or on the tram. My girlfriend and I visited two famous local cities, Düsseldorf and Cologne, which are both on the Rhine River. Düsseldorf is an urban metropolis with a great variety of restaurants. We took a boat tour on the river and went up the Rhine Tower, a really tall building which offers great views across the city. Cologne, as you might know, is world-famous for its perfumes. The cathedral there is an unmissable landmark. We made the effort to climb to the top of one of the cathedral's towers. The spiral (螺旋的) stairs seemed endless, but it was worthwhile for the impressive sights from the top.

    We also went in a cable car over the river and tasted a German delicacy called "Spaghettieis" which is ice cream with strawberry sauce! I also got to try the famous German sausage. I must admit, I really enjoyed the food! The only disappointment was the grey and rainy weather, which proves that Britain does not have the worst weather in Europe!

    The light from the campfire brightened the darkness, but it could not prevent the damp cold of Dennis's Swamp (沼泽地) creeping into their bones. It was a strange place. Martin and Tom wished that they had not accepted Jack's dare. They liked camping, but not near this swamp.

    "So," Martin asked as they sat watching the hot coals. "How did this place get its name?"

    "Are you sure you want to hear it? It's a scary story," warned Jack.

    "Of course!" cried out Tom. "If there were anything to be scared of, you wouldn't have chosen this place!"

    "Ok, but don't say I didn't warn you," said Jack, and he began this tale.

    "Way back in time, a man called Dennis tried to start a farm here. He built that cottage over there to live in. In those days, the area looked quite different—it was covered with tall trees and the swamp was a crystal-clear river. After three hard years, Dennis had cleared several fields and planted crops. He was so proud of his success that he refused to listen to advice.

    "'You are clearing too much land,' warned one old man. 'The land is a living thing. It will hit back at you if you abuse it. '"

    "'Silly fool,' said Dennis to himself. 'If I clear more land, I can grow more crops. I'll become wealthier. He's just jealous!'"

    "Dennis continued to chop down trees. Small animals that relied on them for food and shelter were destroyed. He was so eager to expand his farm that he did not notice the river flowing slowly towards his door. He did not notice salt seeping to the surface of the land. He did not notice swamp plants choking all the native plants."

    "What happened?" Martin asked. It was growing colder. He trembled, twisting his body closer to the fire.

    "The land hit back—just as the old man warned," Jack shrugged. "Dennis disappeared. Old folks around here believe that swamp plants moved up from the river and dragged him underwater. His body was never found."

    "What a stupid story," laughed Tom. "Plants can't …" Before he had finished speaking, he screamed and fainted (晕倒). The other two boys jumped up with fright, staring at Tom. Suddenly, they burst out laughing. Some green swamp ivy (常春藤) had covered Tom's face. It was a while before Tom could appreciate the joke.

    Feel nervous on the first day of school? You are not alone! Here is some advice on how to make you feel comfortable.

    Get ready the night before. Plan out what you're going to wear and what you will need for class. Then get a nice, long sleep. There's nothing worse than looking terrible on the first day of school. If you don't want to oversleep, set an alarm on your phone, or alarm clock to wake you up on time.

    Eat a good breakfast. You'd be surprised at how much happier and more focused you'll be after eating a good breakfast. Have a healthy breakfast. A rich breakfast may make you feel lazy and sugar rich foods may affect your ability to stay focused.

    Decide whether to take the bus, walk, or have a ride from your parents. It's your call. If you want something familiar, take a bus ride and sit next to someone you already know. However, if you are really nervous, you can ask your mom or dad to drive you to school, but expect that there will be heavy traffic.

    Smile and be friendly! You want to seem easy to get along with and that you had the best summer. Smile and be friendly. Instead of coming up as a boring person, compliment people. Everyone needs a little confidence and is happy when praised on the first day of school.