Two of the saddest words in the English language are “if only”. I live my life with the goal of never having to say those words, because they convey regret, lost opportunities, mistakes, and disappointment.

    My father is famous in our family for saying “Take the extra minute to do it right”. I always try to live by the “extra minute” rule.  When my children were young and likely to cause accidents, I always thought about what I could do to avoid an “if only” moment，whether it was something minor like moving a cup full of hot coffee away from the edge of a counter, or something that required a little more work such as taping padding (衬垫)onto the sharp corners of a glass coffee table.

    I don't only avoid those “if only” moments when it comes to safety. It's equally important to avoid “if only” in our personal relationships. We all know people who lost a loved one and regretted that they had foregone an opportunity to say “I love you“ or “I forgive you”. When my father announced he was going to the eye doctor across from my office on Good Friday，I told him that it was a holiday for my company and I wouldn't be here. But then I thought about the fact that he's 84 years old and I realized that I shouldn't give up an opportunity to see him.  I called him and told him I had decided to go to work on my day off after all.

    I know there will still be occasions when I have to say “ if only” about something, but my life is definitely better because of my policy of doing everything possible to avoid that eventuality. And even though it takes an extra minute to do something right, or it occasionally takes an hour or two in my busy schedule to make a personal connection, I know that I'm doing the right thing. I'm buying myself peace of mind and that's the best kind of insurance for my emotional well-being.

    We are all busy talking about and using the Internet, but how many of us know the history of the Internet?

    Many people are surprised when they find that the Internet was set up in the 1960s. At that time, computers were large and expensive. Computer networks didn't work well. If one computer in the network broke down, then the whole network stopped. So a new network system had to be set up. It should be good enough to be used by many different computers. If part of the network was not working, information could be sent through another part. In this way computer network system would keep on working all the time.

    At first the Internet was only used by the government, but in the early 1970s, universities, hospitals and banks were allowed to use it too. However, computers were still very expensive and the Internet was difficult to use. By the start of the 1990s, computers became cheaper and easier to use. Scientists had also developed software that made "surfing" the Internet more convenient.

    Today it is easy to get on-line and it is said that millions of people use the Internet every day. Sending e-mail is more and more popular among students.

    The Internet has now become one of the most important parts of people's life.

    Millions of Americans sit behind a computer screen, chained to their desk all day because the vast majority of stable, high-paying professions(职业) are "office jobs". However, having a successful career does not require you to sit behind a desk and plug away at a computer all day.

    In fact, there are a large number of non-desk jobs in a variety of industries that are growing and offering workers a direct path to the middle class, according to a new analysis of labor market information from CareerBuilder. While most of the highest-paying non-desk jobs are medical professions that require a doctoral or professional degree, there are 170 non-desk professions that pay $15 per hour or more, do not require a bachelor's degree(学士学位) for a typical entry-level position, and have seen at least 6 percent job growth over the last four years.

    "The US workforce has gradually changed to office-based work because of the rise of the professional service economy and productivity gains associated with information technology," Rosemary Haefner, Vice President of Human Resources Officer at CareerBuilder, said in a statement. "But some of the healthiest areas of job growth year after year are in middle-skill professions that don't require workers to sit in front of computer monitors and phones for 40 hours a weel."

    Here are the top-paying jobs that don't require you to work at a desk in various kinds — none of which require a four-year college degree — and their hourly salary(工资) and growth rate since 2010: professional assistants(助理) : $26.57, 14 percent; elevator repairers: $37.81, 6 percent; mechanical engineering technicians: $25.19, 10 percent; and electromechanical(电动机械的) technicians: $24.68, 8 percent.

    While they tend to pay less than traditional office jobs, non-desk professions provide a variety of benefits. Haefner points to a 2014 CareerBuilder survey that discovered workers who don't work at a desk all day are less likely to complain about their work environment and less likely to report being overweight.

    It seems that electronic devices just keep getting smaller. Scientists in the United States have announced the creation of the first transistor with only two dimensions(二维).

    A transistor is a small electronic device that transfers or carries electronic current. Scientists hope these new 2D transistors will be used for building high-resolution(高分辨率)displays that need very little energy.

    Two groups of scientists created these 2D transistors. They report that the transistors are only a few atoms thick.

    Usually transistors are made with the element silicon(硅). Computer processors, memory chips, TV screens and other electronic devices contain billions of silicon-based transistors. But these very small electrical parts have certain limitations.

    Dimitris Ioannou is an electrical engineering professor at George Mason University. He says the traditional transistor has been improved as much as it can be. He adds that researchers have been looking for new materials with special features and they want transistors to be seen through and soft.

    "If the layers are very thin, the transistor can become flexible, so it doesn't have to be rigid(坚硬的), like it would be in a silicon chip. So people can think of applications like wearable electronics, television screens and other things," said Ioannou.

    These new transistors can also carry higher current. They also can move the current much faster than traditional transistors. This is important for high-definition screens.

    Dimitris Ioannou says the scientific success could prove very useful in the future. "Now, how good and how useful it will be, it's still in the stage of research, but it certainly is an advance," said Ioannou.