Why do human beings still risk their lives under ground and doing one of the dirtiest and most dangerous jobs in the world? It is an increasingly urgent question, given the recent mining accidents in Sago, W. Va and Huntington, Utah. A small group of engineers and robotics experts look forward to a day in the not-too-distant future when robots and other technology do most of the dangerous mining work.

    Robotic technology, in particular, holds much promise, McAteer says, especially when it comes to mapping mines and rescuing trapped miners — the special operations of the mining industry.

    One of the first mining robots was developed five years ago at Carnegie Mellon University's Robotics Institute. It was called Groundhog. It used lasers(激光器) to “see” in dark tunnels and map abandoned mines—some of the most dangerous work in the business.

    The latest design is called Cave Crawler. It's a bit smaller than Groundhog, and even more advanced. It can take photos and videos and has more sensors that can detect the presence of dangerous gases. Incredibly, the robot has a real sense of logic. If it comes across an obstacle it gets momentarily confused. It has to think about what to do and where to go next. Sometimes it throws a fit just like a real person.

    The greatest problem, though, is cost. The money of the earliest research project was provided by the government, but that money had dried up, and it's not clear where future money will come from. Partly for that reason, and partly because of advances in safety, mining is not nearly as dangerous as it was in the past. Since 1990, fatalities(致命性) have declined by 67% and injuries by 51% , according to the National Mining Association.

    Some experts predict that robots in mines will serve much of the same function that they do in the automotive industry. The robots do the most boring and dangerous jobs，but won't get rid of the need for human workers.

    We walked in so quietly that the nurse at the desk didn't even lift（抬起）her eyes from the book.Mum pointed at a big chair by the door and I knew she wanted me to sit down.While I watched,mouth open in surprise.Mum took off her hat and coat and gave them to me to hold.She walked quietly to the small room by the lift（电梯）and took out a wet mop（拖把）.She pushed the mop past the desk and as the nurse looked up.Mum nodded and said,"Very dirty floors."

“Yes.I'm glad they've finally decided to clean them,”the nurse answered.She looked at Mum strangely and said. “But aren't you working late?”

    Mum just pushed harder,each swipe of the mop taking her farther and farther down the hall.I watched until she was out of sight and the nurse had turned back to writing in the big book.

    After a along time Mum came back.Her eyes were shining.She quickly put the mop back and took my hand.As we turned to go out of the the door,Mum nodded politely to the nurse and said.“Thank you.”

    Outside,Mum told me, “Dagma is fine.No fever."

     “You see her,Mum?”

     “Of course.I told her about the hospital rules,and she will not expect us until tomorrow.Dad will stop worrying as well.It's a fine hospital.But the floors!A mop is no good.You need a brush."

    I've seen a couple of the other Fast Furious films but this one is definitely best. Dominic Toretto (played by Vin Diesel), Brian O' Conner (Paul Walker) and Mia Toretto (Jordana Brewster) are planning to steal $100 million from businessman Hernan Reyes (Joaquim de Almeida). At the same time, agent (联邦特工) Luke Hobbs (Dwayne Johnson) is chasing after them. The story's pretty fast-moving and the car chase at the end is amazing.

—Derek

    Well, if I'd known it was an action film, I wouldn't have gone to see it. I mean, I can't stand action films. And I'll tell you another thing – I can't stand Vin Diesel. I mean he can't act to save his life. The film would have been much better with someone like Mau Damon or George Clooney. The only good thing about it was the soundtrack (电影配乐) which was pretty good. And I won't be going to see any other Fast & Furious movies either!

—Zoe

    Well it started off all right, but the romance between Mia and Brian was a bit inadequate (不足的) and the whole thing lost its way. It was as if the director couldn't decide whether he was making a thriller, an action movie or a romantic comedy (喜剧), so he ended up making none of them.

—Mario

    It was amazing! I can't believe it was really over two hours long. It just flashed by. The direction was superb； Justin did a really good job. And the acting was great. I know Vin Diesel isn't going to win an Oscar or anything like that but he's good at what he does. And the plot! I laughed out loud quite a few times. The funny thing is, I wouldn^'t have bothered seeing it if my friend hadn't suggested going.

—Megan

    Have you ever wondered why birds sing? Maybe you thought that they were just happy. After all, you probably sing or whistle when you are happy.

    Some scientists believe that birds do sing some of the time just because they are happy. However, they sing most of the time for a very different reason. Their singing is actually a warning to other birds to stay out of their territory.

    Do you know what a "territory" is? A territory is an area that an animal ,usually the male, claims(声称)as its own .Only he and his family are welcome there. No other families of the same species(物种)are welcome. Your yard and house are your territory where only your family and friends are welcome. If a stranger should enter your territory and threaten you, you might shout. Probably this would be enough to frighten him away.

    If so, you have actually scared the stranger away without having to fight him. A bird does the same thing. But he expects an outsider almost any time ,especially at nesting(筑巢)season. So he is screaming all the time, whether he can see an outsider or not. This screaming is what we call a bird's song, and it is usually enough to keep an outsider away.

    Birds sing loudest in the spring when they are trying to attract a mate and warn others not to enter the territory of theirs.

    You can see that birds have a language of their own. Most of it has to do with attracting mates and setting up territories.

    A five-year-old dog named Kelsey has been praised as a hero for helping to save the life of her owner who slipped in the snow and broke his neck.

    The man, Bob, was alone when he left his Michigan farmhouse on New Year's Eve to collect firewood. Expecting a journey of only several meters, Bob was wearing just long johns (衬裤), a shirt and slippers when he went outside, although the temperature was around -4℃.

    After the accident, he was unable to move in the snow. Fortunately, Kelsey came to his assistance.

    "I was shouting for help, but my nearest neighbor is about 400 meters away, and it was 10:30 pm, Bob explained." But my Kelsey came. By the next morning, my voice was gone and I couldn't yell for help, but Kelsey didn't stop barking."

    Kelsey's companion kept him warm by lying on top of him. She licked his face and hands to keep him awake." Kelsey kept barking but never left my side," Bob recalled. "She kept me warm. I knew I couldn't give up and that it was my choice to stay alive."

    Bob spent 20 hours in the freezing cold. When he finally lost consciousness, his dog kept barking. Finally, hearing the barking, Bob's neighbor discovered him at 6:30 pm on New Year's Day and called the emergency services at once. When Bob arrived in hospital, his body temperature was below 21℃. However, doctors were surprised to find that he didn't have any frostbite (冻疮). They believed it was because of Kelsey's determination to keep him warm, Dr. Chaim Colen, the doctor who treated Bob, said, "Animals can help and his dog really saved him... He was very fortunate.”

    Bob said he was "enormously" grateful to both Dr. Colen and his Kelsey, "They saved my life. They are truly heroes!"

    I'd like to share a little story with you about something that happened when I was four. I remember it clearly. Our loving family dog was nearing the end of his life. My father picked him up and put him in a little bed we had made for him. Our dog, my companion, whom we had cared for, bit my father when he attempted to help him. How could he? Why? I couldn't understand it. I didn't like him anymore.

    I hadn't thought about that story for a long time but something that happened last week brought it back to me. I went to speak with a friend. When I knocked on the door, I met in an instant an angry look and a few harsh(尖刻的)words. When the door was slammed(砰地关上)in my face, I stood there shocked, and in a rush, I was reminded of my dog bit my father 20 years ago or so. What brought that story back was that same feeling of betrayal.

    Both stories taught me something the next day. You see, when I got up in the morning and was told my dog had died, it became clear to me that he must have been in great pain. For him to have bitten a family member, he could not have been himself. Much the same for the other story when I learned that my friend's wife had just left him.

    We are all beings of our environments, our opinions and feelings. And all of those things can cause you to say and do things that can't be understood by those who are not in the same situation with you.

    If you meet someone either behaving out of character or acting in a way that doesn't seem to fit the situation, put out your hand and be patient when you think it is least possible for him to do so. You may turn around a story that has a sad ending simply by your actions.