Here are four principles (行为准则) I live by. Whenever I follow these guidelines, I am at my very best, feeling productive and happy.

Devote time.

No matter how talented we may be, it’s wrong to think we can do it all. 【小题1】 The value of our achievements is greatly decided by what we spend our time on. We need to realize that every day we should devote the time to what matters and have the courage to let the unimportant things go.

Focus your attention.

Very often it seems that we just can’t focus our attention, even though we know what we should be doing, right? Resistance (阻力) makes us get disturbed by distractions.【小题2】 Developing a plan for overcoming resistance is important for maximum productivity.

【小题3】

We need to make a balance between work and play, between creation and pleasure.【小题4】 Even if we feel energetic to work long hours, the most effective long-term way is to hold ourselves back when we feel crazy and follow a proper pace instead.

Keep moving on.

More important than setting big goals is to just keep going. I know this goes against most of the “ set great goals for yourself” advice, but it’s what works for me.【小题5】 And it always made me more worried than it helped. Now, what does work for me is to think about how to improve my life and take small steps to make it happen.

Global warming could make humans shorter, warn scientists who are said 【小题1】（find）evidence that it caused the world’s first horses to shrink nearly 50 million years ago.

In fact, a team from the universities of Florida and Nebraska says it has found a link between the earth 【小题2】（heat）up and the size of mammals — horses. The scientists used fossils to follow the evolution（进化）of horses from their earliest 【小题3】（appear）56 million years ago.

“As temperatures went up, 【小题4】（they）size went down, and vice versa; at one point they were as small as a house cat,” said Dr. Jonathan Bloch, curator of the Florida Museum of Natural History. The scientists say that the current warming could have the same effect 【小题5】 mammals — and could even make humans 【小题6】（small）.

Horses 【小题7】（start）out small, about the size of a small dog like a miniature schnauzer.【小题8】 is surprising is that after they first appeared, they then became even smaller and then dramatically increased in size, and that 【小题9】（exact）agrees with the global warming event. “It had been known that mammals were small when it was warm,【小题10】 we hadn’t understood that the temperature really was driving the evolution of body size,” Dr. Bloch said in the Science journal.

   Isaac Asimov is one of the most famous science fiction（科幻小说）writers of all time. He moved from Russia to the United States in 1923.He was a teacher at Boston University and began writing science fiction stories in 1939.His most famous works are the Foundation books and the Robot stories. He died in 1992 at the age of 72.

"There are not many people who have invented a useful scientific term，and although I did it unknowingly，I am not going to let anyone in the world forget it，"said Isaac Asimov. He was talking about the word "robotics" —the study of robot behaviour.

Asimov wrote several stories about robots between 1940 and 1990.One of the special features of the robots in these stories was that they were programmed to follow the Three Laws of Robotics.

The First Law: A robot must not hurt a human being，or allow a human being to be hurt.

The Second Law: A robot must obey orders by human beings unless these orders conflict（冲突）with the First Law.

The Third Law: A robot must protect itself unless this conflicts with the First or Second Law.

In Asimov's stories，the robots must follow these laws so that they do not attack the humans that created them.

Some scientists think the Three Laws of Robotics are hard to realise in real life. On the other hand，some say that the laws are great for science fiction but completely useless in real life. For example，if the laws really worked，robots couldn't be used in wars，as this would break the First Law. Since the army is one of the biggest supporters for robotic research，it is very unlikely that an attempt to follow these rules will happen.

According to Asimov，one thing is certain："Robots are changing the world and driving it in directions we cannot clearly foresee（预见）."

   If you could have one superpower, what would it be?

Dreaming about whether you would want to read minds, see through walls, or have superhuman strength may sound silly, but it actually gets to the heart of what really matters in your life.

Every day in our work, we are inspired by the people we meet doing extraordinary things to improve the world.

They have a different kind of superpower that all of us possess: the power to make a difference in the lives of others.

We’re not saying that everyone needs to contribute their lives to the poor. Your lives are busy enough doing homework, playing sports, making friends, seeking after your dreams. But we do think that you can live a more powerful life when you devote some of your time and energy to something much larger than yourself. Find an issue you are interested in and learn more. Volunteer or, if you can, contribute a little money to a cause. Whatever you do, don’t be a bystander. Get involved. You may have the opportunity to make your biggest difference when you’re older. But why not start now?

Our own experience working together on health, development, and energy the last twenty years has been one of the most rewarding parts of our lives. It has changed who we are and continues to fuel our optimism about how much the lives of the poorest people will improve in the years ahead.

   Forty percent of teens say they have been hit or nearly hit by a car，motorcycle or bike while walking，according to a new report released by the Safe Kids Worldwide organization.

Safe Kids Delaware has released a list of safety tips children and teens should follow in order to remain safe while walking. The group said it is important to put down phones and remove headphones while crossing the street，make eye contact with drivers before crossing，and remain visible to drivers even in the dark.

"We all know about the dangers of distracted（思想不集中的）driving，but we need to talk to our children，especially teens，about the dangers of walking while they are distracted by using technology like listening to music with headphones on，and texting on cellphones，"said Kim O'Malley，the pedestrian（行人）safety conductor for Safe Kids Delaware.

Teens on the Moue is the name of the report，which explores the walking behavior of  1，040 teenagers between the ages of 13 to 19.Half of the surveyed teens admitted they were distracted by a mobile device while crossing the street. The study also found that more often than not，those who were hit or nearly hit had not been using a crosswalk（人行横道）or had been running across the street.

Safe Kids Worldwide reports that the death rate for teens aged 13 to 19 is nearly three times higher than that of 5-to 12-year-olds.In Delaware，seven teenagers aged 15 to 19 have been killed in pedestrian crashes in the last three years，and another 123 have been injured. By comparison，just two children aged 5 to 9 were killed at that time and another 79 were injured. The new report expands on findings from a similar one in 2015 that showed one in five high schoolers and one in eight middle schoolers crossed the street while distracted by using technology.