Do you know of anyone who uses the truth to deceive(欺骗)? When someone tells you something that is true, but leaves out important information that should be included, he can give you a false picture．

    For example, someone might say, “I just won a hundred dollars on the lottery(彩票). It was great. I took that dollar ticket back to the store and turned it in for one hundred dollars!”

    This guy is a winner, right? Maybe, maybe not. We then discover that he bought $ 200 worth of tickets, and only one was a winner. He's really a big loser!

    He didn't say anything that was false, but he left out important information on purpose. That's called a half-truth. Half truths are not technically lies, but they are just as dishonest.

    Some officers often use this trick. Let's say that during Governor Smith's last term, her state lost one million jobs and gained three million jobs. Then she tries another term. One of the persons who don't support her says, “During Governor Smith's term, the state lost one million jobs!” That's true. However, an honest statement would have been, “During Governor Smith's term, the state had a net gain of two million jobs.''

    Advertisers will sometimes use half—truths. It's against the law to make false statements so they try to mislead you with the truth. An advertisement might say, “Nine out of ten doctors advised their patients to take Yucky Pills to cure toothache. ”It fails to mention that they only asked ten doctors and nine of them work for the Yucky Company.

    This kind of thing happens too often. It's a sad fact of life: Lies are lies, and sometimes the truth can lie as well.

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    When a computer works on a group of programs, it can get very hot. Cooling the computer can cost a lot. So some scientists wonder what would happen if the heat from the computer could be used.

    Large Internet companies (公司）such as Google and Microsoft have thousands of computers. As these computers deal with information, they produce lots of heat, so they need huge cooling systems(系统）. These systems send the heat into the air.

    A company in Holland(荷兰） thinks paying to make the computers work and then paying again to cool them are a waste of energy. So the company developed a special device—the e-Radiator.

    Boaz Leupe, head of the company, says the e-Radiator works as a heating system and saves money. He explains that the energy is used twice—once to heat the home and once to cool the computer and that the users don't have to pay to cool their computers.

    Five homeowners in Holland are testing the heating system in their homes.

    "We pay for the computer using, so, in that way, homeowners get heating for free," Boaz says.

    Jan Visser is one of the homeowners. "If you use the computer more, the e-Radiator produces more heat," he says. "It can't provide enough heat if you don't use your computer often." But he is ready to try it. It's a great help for his family.

    The company says e-Radiators produce heat temperatures of up to 55℃. It says the system could save its users about $440 a year.

    What do you usually do on your smartphone? Send text messages, make phone calls or play video games? Now, thanks to a beginner-friendly programming（程序设计） tool, kids can do more than just play games on their smartphones-they can make their own games.

    US high school student Samuel Ndungi spent a few months learning how to make apps（应用软件）for smart-phones.

    "I was really shocked that you could do this on your own," Ndungi said "I thought only people from Microsoft and big companies could do this."

    Ndungi took a class run by his teacher, Michael Braun. In Braun's class, kids learned how to use the beginner-friendly programming tool to program their own mobile apps.

    This tool is called TouchDevelop. It puts basic instructions（基本指令） into blocks of code（代码）, and kids can put them together like Legos to run games, stories and other apps.

    With TouchDevelop, student Tony Huynh learned how to make his own games. "You get to put your own thoughts into the game, like the animals you want, the kinds of backgrounds you would like to see, and so on," he said.

    Another student Shina Williams wrote a program with about 80 lines of code that paints a picture of his childhood Teddy Bear." It's your own creativity, your own mark（印记） of something that's put in there and it stays in there, " she said.

    Coding is more than just a job skill. Children who learn coding also find new ways to think, create and express themselves.

    What was discovered by accident? The answer is penicillin (青霉素). It kills germs. By killing germs, it saves lives. Suppose you are sick. You go to a doctor. She examines you. She says you have a "staph" infection (葡萄球菌感染). She gives you some medicine. You take it. The medicine knocks out the staph. Soon you are well. Before penicillin, this would not happen. Staph was almost sure death.

    Everyone wanted a medicine. Laboratories worked day and night. They grew the staph in small dishes. Then they tried to kill it. Nothing worked.

    The laboratory dishes had covers on them. They kept things from falling into dishes. Molds (霉菌) were a big worry. They are always in the air. You can't see them. They're too small. There are thousands of different molds. Molds can make an experiment fail. That's why dishes are covered.

    Dr. Alexander Fleming was working to kill the staph germ. He worked for years. One day he took a cover off a dish. He looked inside. There was a thick growth of staph germ. There was also some mold. Then he saw something strange. Where the mold was, there was no growth of staph. This is what Fleming probably thought. "By accident, I found a mold to kill the dreaded staph."

    This is how penicillin was found. But here's the real miracle. There are thousands of kinds of molds. But only one kind can kill staph. The mold must have fallen into the dish a few days before. The cover was probably off only a few seconds. In those few seconds the right mold fell into the right dish. Another man might have thrown the dish away. But Fleming was very careful and smart. He understood what the mold did. How lucky the humans were!

    Technology is everywhere. In fact, almost all of us carry a certain piece of technology with us every time we leave the house. What I always forget, though, is just how useful and powerful technology can be when we want to help others.

    There is not a single room in my house that does not have some electronic devices(设备).Whenever I am at home, I am almost always using at least one electronic device. If you walk into my living room on any given day, you will find that, first, I have the television on. At the same time, I usually have my laptop resting on my knee, or I am using my mobile phone. Even when I'm not at home, I am always using my phone, and at work or in cafes, I sit down and connect to the local wireless network on my laptop.

    I must say that I waste a lot of time on the computer and the time I spend on it could be much better spent if I were to take up a little online volunteering.

    Recently I discovered just how much online volunteering there is to do in the world. From using your language skills to do translations, to developing and managing projects and helping with IT work, there is so much that so many people can do to help people in their own countries and across the world. The United Nations, in fact, has a huge page with "Volunteers Recruited" on its website.

    This work can support the poor and help charities who cannot pay for staff members. Many organizations only require you to work an hour a week, some even less. And the support provided by online volunteers can really help make a difference to those in need.