It was a hot,humid day, and my brother Walt and I had decided that the only way to surviveit would be to go swimming in a deep swimming hole across Mr. Blickez's pasture(牧场) and through some woods.

    The onlyproblem with our plan was that this pasture was guarded by a huge, meanHereford bull. Mr. Blickez had told us that Elsie was the meanestbull in the township, maybe even the county, and we believed him. But the hotter it got, the more we thoughtthere was something fishy about his claim. For one thing, we remembered Mr. Blickez liked telling tall tales; for another, Elsie seemed like an oddname for a bull.

    Finally, Italked Mom into asking permission for us to walk through the pasture, but thenanother problem surfaced．Mom said she would talk to Mr. Blickez if we would take our cousin Joanie along with us. Joanie was almost two years older than me anda head taller. If her teasingever got around my grade school, it would be all over for me. In fact, I still had a headache from a quarrelwith her that morning.“I'm not goingswimming with that dumb girl cousin.” I told my mom.

  “Either Joaniegoes with, or you stay home alone,” Mom said in her serious tone. I gave in and we set out. On our way across the pasture, Walt yelledsuddenly. Elsie hadapproached him quietly and was licking(舔) his back. Joanie and Idove under the wire fence, but while I was on the ground I looked up and sawthat Elsie wasn't a big mean bull after all. She was going to keep licking my brother's back as long as he stoodstill.

    We had manygood days growing up and visiting our secret swimming hole guarded by theso-called “big mean bull”. And as it turned out, for a girl cousin, Joanie hasn't been too bad. She's been one of my best friends over theyears.

    Today's Flight Time Table

（Departure＝leave）

    Robots make me nervous—especially the ones which seem to think for themselves. I was embarrassed to admit this till I heard that Bill Gates, the founder of Microsoft, felt the same way.

    Gates said in an interview with the social networking and news website Reddit: "I am in the camp that is concerned about super intelligence. First the machines will do a lot of jobs for us and not be super intelligent．That should be positive if we manage well. A few decades after that, though, the intelligence is strong enough to be a concern."

    Well, maybe I don't have to worry about my computer and kitchen equipment yet. After I use them I can always pull the plug. But in the future, machines might find a way to prevent us from switching them off. There's a terrible thought!

    Maybe the problem with computers too clever for us is not that they are evil like some we've seen in sci-fi movies. What could put us in danger is that they might be too efficient. That's what philosopher Nick Bostrom from Oxford University believes. He says that machines are indifferent to humans and in pursuit of their own goals，the destruction of people might be just additional damage. Bostrom gives us an example: A machine which might have its only goal to produce as many paperclips as possible might look at human bodies as extra material for paperclips and go after you. Because it is, well, a machine, it would not take pity on you.

    It's a good thing that American writer Isaac Asimov thought about how far robots can go and left us his three rules of robotics. They state that a robot may not hurt a human being or allow the human being to come to harm.

    I'm glad my machines at home are "dumb". All my cleaner wants to take over is the carpet in my living room. Let's hope they don't create an appliance which wants to take over the world!

    Reintroducing beavers (海狸) to Britain could help clean up rivers, prevent flooding and minimise soil loss, an expert has claimed.

    Professor Richard Brazier, a researcher at the University of Exeter, said unpublished results from a trial area in Devon showed muddy water entering an area where beavers were living was three times cleaner when it left. "Our trial has shown that the beavers are able to dam our streams in a way that keeps soil in the headwaters of our catchment (流域) so it doesn't block up rivers downstream and pollute our drinking and bathing waters. If we bring beavers back it's just one tool we need to solve Britain's crisis of soil loss and agricultural pollution of waterways, but it's a useful tool," he said.

    Prof Brazier's claims were disputed by the National Farmers' Union (NFU), which warned that the reintroduction of beavers to Scotland had led to fields and forests becoming damaged. Spokesman Mark Pope said: "The knowledge of the impacts beavers have had on farmland, riverbanks and flood defences in Scotland is concerning. We await the results of the Devon trial and will analyse the outcomes then."

    Prof Brazier, an expert in Earth Surface Processes, insisted the animals could even play a useful role in preventing flooding. He told BBC News: "The public is currently paying people to build leaky dams to keep storm waters in the uplands. The beavers can do it free of charge and even build their own homes."

    However, Professor Jane Rickson, a soil specialist from Cranfield University, Bedfordshire, joined the NFU in sounding a note of caution. She agreed that in some places in the UK there was evidence of worrying soil loss, and said new policies were urgently needed. Beavers may in fact reduce the river channel and remove vegetation, exposing banks to greater erosion (侵蚀) and increasing, rather than decreasing, the risk of flooding, she warned. And she said beaver dams should be "leaky" to avoid build-ups of large volumes of water.

    Cooperation at work is generally seen as a good thing. The latest survey by the Financial Times of what employers want from MBA graduates found that the ability to work with a wide variety of people was what managers wanted most. But managers always have to balance the benefits of teamwork, which help ensure that everyone is working towards the same goal, with the dangers of “groupthink” when critics are reluctant to point out a plan's drawbacks for fear of being kept out of the group. The disastrous Bay of Pigs invasion of Cuba in 1961 was a classic case of groupthink. Skeptics were reluctant to challenge John F. Kennedy, the newly elected American president.

    Modern communication methods mean that cooperation is more frequent. Workers are constantly in touch with each other via e-mail messaging groups or mobile calls. But does that improve, or lower performance? A new study by three American academics, tried to answer this question. They set a logical problem (designing the shortest route for a travelling salesman visiting various cities). Three groups were involved: one where subjects acted independently; another where they saw the solutions posted by team members at every stage; and a third where they were kept informed of each other's views only intermittently.

    The survey found that members of the individualist group reached the premier solution more often than the constant cooperators but had a poorer average result. The intermittent cooperators found the right result as often as the individualists, and got a better average solution. When it comes to ideal generation, giving people a bit of space to a solution seems to be a good idea. Occasional cooperation can be a big help: most people have benefited from a colleague's brainwave or (just as often) wise advice to avoid a particular course of action.

    Further clues come from a book, Superminds, by Thomas Malone of the Massachusetts Institute of Technology. He says that three factors determine the collective intelligence of cooperating groups: social intelligence (how good people were at rating the emotional states of others); the extent to which members took part equally in conversation (the more equal, the better); and the cooperation of women in the group (the higher, the better). Groups ranked highly in these areas cooperated far better than others.

    In short, cooperation may be a useful tool but it doesn't work in every situation.

There are thousands of puzzles to choose from for you, such as jigsaw puzzles, puzzle books and more. They all have something in common: they test your skills or knowledge. Here are four of the most common:

Word puzzles

One of the most popular word puzzles — the crossword. It can be done with paper and pencil or online. Sometimes word puzzles involve finding new words within a large group of letters. This type of word puzzle is called a word search.

Word puzzles usually test your vocabulary. Knowing the language that the game is designed in is required for success, however.

Mechanical puzzles

Mechanical puzzles have pieces that must be arranged in some way. The world's best-selling puzzle, the Rubik's Cube, is a mechanical puzzle. As of 2020, over 450 million Rubik's Cubes had been sold.

Jigsaw puzzles also fall into this category. They typically involve putting pieces in the right place to form a picture. Jigsaw puzzles have from two to over 550,000 pieces — the largest one on record.

Logic puzzles

Figuring out the solution to a logic puzzle requires careful thought rather than guessing. Sudoku and Mine Finder are examples of logic puzzles. In Mine Finder players must determine where the mines are hidden in a grid.

Math puzzles

Math puzzles involve numbers, words or objects and the use of math. Surprisingly, the ever-popular Candy Crush is classified as a math puzzle. Math skills are required for players to successfully move and match colored candies.

There are many other kinds of puzzles. But no matter which you prefer, puzzles are a great way to entertain.