Here is an astonishing and significant fact: Mental work alone can't make us tire. It sounds absurd. But a years ago, scientists tried to find out how long the human brain could labor without reaching a stage of fatigue (疲劳). To the amazement of these scientists, they discovered that blood passing through the brain, when it is active, shows no fatigue at all! If we took a drop of blood from a day laborer, we would find it full of fatigue toxins(毒素) and fatigue products. But if we took blood from the brain of an Albert Einstein, it would show no fatigue toxins at the end of the day.

    So far as the brain is concerned, it can work as well and swiftly at the end of eight or even twelve hours of effort as at the beginning. The brain is totally tireless. So what makes us tired?

    Some scientists declare that most of our fatigue comes from our mental and emotional(情绪的) attitudes. One of England's most outstanding scientists, J.A. Hadfield, says, “The greater part of the fatigue from which we suffer is of mental origin. In fact, fatigue of purely physical origin is rare.” Dr. Brill, a famous American scientist, goes even further. He declares, “One hundred percent of the fatigue of sitting worker in good health is due to emotional problems.”

What kinds of emotions make sitting workers tired? Joy? Satisfaction? No! A feeling of being bored, anger, anxiety, tenseness, worry, a feeling of not being appreciated—those are the emotions that tire sitting workers. Hard work by itself seldom causes fatigue. We get tired because our emotions produce nervousness in the body.

    Many facts suggest that children are overweight (超重的) and the situation is getting worse, according to the doctors. I feel there are a number of reasons for this.

    Some people blame the fact that we are surrounded by shops selling unhealthy, fatty foods, such as fried chicken and ice cream, at low prices. This has turned out a whole generation of grown-ups who seldom cook a meal for themselves. If there were fewer of these restaurants, then probably children would buy less take-away food.

    There is another argument that blames parents for allowing their children to become overweight. I agree with this, because good eating habits begin early in life, long before children start to visit fast food shops. If children are given fried chicken and chocolate rather than healthy food, or are always allowed to choose what they eat, they will go for sweet and salty foods every time, and this will carry on throughout their lives.

    There is a third reason for this situation. Children these days take very little exercise. They do not walk to school. When they get home, they sit in front of the television or their computers and play computer games. Not only is this an unhealthy pastime (消遣), it also gives them time to eat more unhealthy food. What they need is to go outside and play active games or sports.

    The above are the main reasons for this problem, and therefore we have to encourage young people to be more active, as well as steering them away from fast food shops and bad eating habits.

    Google's new artificial intelligence can defeat both humans and other AIs. Fortunately, the only war zone where it fights and wins is the ancient board game Go（围棋）.

    AlphaGo Zero, developed by Google-owned DeepMind, is the latest AI program. The original AlphaGo defeated Go master Lee Sedol last year, and AlphaGo Master, an updated version, went on to win 60 games against top human players. What's different about AlphaGo Zero is that it became potentially the world's best Go player without any help from humans.

    The program AlphaGo Zero started off knowing only the basic rules and then played millions of games against itself in just a few days. After almost five million games played against itself, AlphaGo Zero could outplay humans and the original AlphaGo. After 40 days, it was capable of beating AlphaGo Master.

The program learned the strategies humans accumulated over thousands of years in a matter weeks and also developed nontraditional strategies and moves that beat the techniques of the human masters, leaving them astonished. "At each stage of the game, it seems to gain a bit here and lose a bit there, but somehow it ends up slightly ahead, as if by magic," said Andrew Jackson of the American Go Association

    DeepMind says it has plans for the technology behind AlphaGo Zero beyond just defeating all over an ancient game board. "In the end, we want to apply these breakthroughs to helping solve all sorts of pressing real world problems like designing new materials," said Demis Hassabis, co-founder and CEO of DeepMind, in a statement.

    That sounds great, but just as a precaution, let's take the advice of Elon Musk and Stephen Hawking and keep any super-fast learning AI away from the nuclear launch codes for now.

    Mr. Parker was born in a small village. His father was so poor that he couldn't send him to school. The boy had to help his parents to do some farming and learned English and maths by himself when he was free. Later on he was made to leave his home village and hoped to find a job in a city. And as soon as war broke out, he joined the army. He couldn't forget his terrible past and fought with the enemies bravely. So he became a general when he was fifty. He was honest and friendly to his soldiers and often punished those who tried to pocket a portion of the soldiers' pay (克扣军饷). And his soldiers liked him very much.

    Once Mr. Parker heard from a soldier. In the letter the young man said the food in their military camp was very bad and he wished the general could go to find out the reasons, the old man went there at once, without telling anybody. He went in the kitchen and examined everything carefully and found it was very dirty. Then he went in the soldiers' bedrooms and found there were a lot of fleas. He became angry and asked the soldiers, “What do you think of your food, young men?”

    The soldiers saw their officer standing by the general and said nothing Only a new soldier said, “Very bad, sir!”

    “What did you have for lunch today?” asked Mr. Parker.

    “A fried chicken, some fish and pork, a cake, six eggs and I had three cups of wine.”

    “Really?” Mr. Parker called out in surprise. “It's the King's lunch, I think!”

    “So do I. General,” said the young man. “But it's my birthday today. I paid three hundred dollars for them all in the restaurant!”

    The weather is very important to farmers. The calendar might say “August”， but the weather's more like October. For some farmers the cool weather is a good thing. For others, it's a cause for concern.

    At Apple Hill, the cooler weather was giving the Boeger Winery a chance to concentrate on bottling instead of picking. “Things were really maturing, it has just been a welcome relief to have more time to prepare.” said Greg Boeger of Boeger Winery.

    But down in the Delta, the earlier hot weather has them two weeks ahead of schedule. Their harvest actually started on Tuesday, and this cooling trend is a worry. There have been no problems yet, but for each of the last two years heavy rain right after Labor Day was a problem, one that Don Pylman would not like to see repeated.

    “If it doesn't start raining, we're in good shape，” said Pylman. “If the sun comes out and clears up we can get right back to work, but if we do get rain, the rots will start.”

    The kind of grape makes a difference as well. Thin­skinned grapes like the chardonnay variety are much more sensitive to rain than some of the others. They're also more difficult to dry off.

One fine day, a bus driver went to the bus garage, started his bus, and drove off along his route. No problems for the first few stops—a few people got on, a few got off, and things went generally well.

At the next stop, however, a big hulk of a guy got on. Six feet eight, built like a wrestler, arms hanging down to the ground. He glared at the driver and said, "Big John doesn't pay!" and sat down at the back. The driver was five feet three, thin, and basically mild-mannered. Naturally, he didn't argue with Big John, but he wasn't happy about it.

The next day the same thing happened—Big John got on again, made a show of refusing to pay, and sat down. And the next day, and the one after that, and so forth.

This grated on the bus driver, who started losing sleep over the way Big John was taking advantage of him. Finally he could stand it no longer. He signed up for body building courses, karate, judo, and all that good stuff. By the end of the summer, he had become quite strong—what's more, felt really good about himself.

So on the next Monday, when Big John once again got on the bus and said. "Big John doesn't pay!" the driver stood up, glared back at the passenger, and screamed, "Oh, yeah? And why not?" With a surprised look on his face, Big John replied, "Big John has a bus pass."