Angad Rekhi, a graduate student and an assistant professor of electrical engineering, has developed a wake-up receiver. This wake-up receiver has many potential applications, particularly in designing the next generation of net worked devices, including so called "smart" devices that can communicate directly with one another without human intervention (介入).

    Once attached to a device, a wake-up receiver listens for a unique ultrasonic（超声波）pattern that tells it when to turn the device on. It needs only a very small amount of power to maintain this constant listening, so it still saves energy overall while extending the battery life of the larger device. A well-designed wake-up receiver also allows the device to be turned on from a significant distance.

    Given the increased interest in networked devices, researchers and industry organizations are starting to define what features and techniques will become standard. Regardless of whether this ultrasound wake-up receiver is among these standard designs, it is likely wake-up receivers of some kind will be combined into commercial applications soon.

    By comparison, the ultrasound wake-up receiver requires a battery but has much greater range than the wirelessly powered devices, while still maintaining a long lifetime due to extremely low power draw. These two technologies-wireless power and wake-up receivers-would likely serve different purposes but both indicate at a turning point in devices that make up the Internet of Things.

    "In light of a long-promised future where interconnected, autonomous, widespread and unremarkable technologies make life easier, the networked devices available now, like video doorbells and app-enabled lights, seem like rather slight advances." the researchers said. They believe technologies like theirs could help cross the gap between the Internet of Things as we know it and the Internet of Things at its best-whatever that may be.

    Have you ever wondered what the longest word in the English language is? Believe it or not, there's no simple answer to the question. You might think it would be as easy as opening a dictionary and looking for the longest word. However, it's far more complicated (复杂的) than that.

    Over time, many people have suggested many different words for the title of the longest word in English. How can that be? That's because the first thing that people have different opinions on is what should be considered a word. Some of the words were simply made up to be the longest! For example, there is one really famous long word that most kids know. It comes from Disney's movie Mary Poppins: supercalifragilisticexpialidocious, which means wonderful. But since that 34-letter word was made up simply to be sung as a song in a movie, should it count?

    How about long words that actually describe something in the world? Scientists have come up with several possible choices. The name of a virus(病毒) totals 1,185 letters. There's also a protein(蛋白质) whose name totals 1, 909 letters. Should these win the title? "Not so fast!" say some people. Are these words ever actually used? Can they even be pronounced? And are they meaningful just because they are made up to be long?

    If you're wondering about some long words in common English, here are some examples. Those words include uncharacteristically (20 letters), deinstitutionalization(22 letters) and counterrevolutionaries (also 22 letters) Or perhaps the word "smiles" is the longest word in English. Sure, it has only six letters, but there is a "mile between the first and the last letters!

    The United States of America is mainly an English-speaking country. The majority of the population speak English as their native language. Besides, education, social activities, etc. are conducted in English. Across but for the most part, Americans speak one common language. This language is sometimes called American English.

    However, not everyone in the USA is a native speaker of English. Most immigrants (移民)are speakers of other languages. There are hundreds of communities around the USA where English is not the most commonly used languages. Chinese, Italian, German, Greek, Spanish and French are all spoken in various communities in the USA. Spanish is the second most commonly spoken language after English. It is widely spoken in New York and across the southern part of the country. For speakers of other languages, learning English is important, but teaching people to speak English as a second language was given little attention. Non-English speakers were expected to "pick up" the language by meeting with others in public. Recently, this has changed.

    Today, most large public schools and community colleges have ESL(English as a Second Language )programs; American English teachers feel that English students should learn the language the way they will use it. Therefore, ESL programs offer different English lessons to different students. Some programs teach students to communicate in English in public. Other programs teach the kind of English people who will need for their jobs. American ESL instructional methods do not lay emphasis on grammar or translation, but on the importance of communication. The goal is to get the English learners to learn by using the language.

    When my father married my mother in 1943, he gave my mother a 1937 crown coin and told her to keep it in the back of her purse and not to spend it. This would mean that she always felt that she was protected and would always have money if she really needed it.

    When I was married in 1970 my husband who had heard this story, obtained a 1937 crown coin for me and I have always kept it in my wallet, and I have always had enough for my needs.

    A friend recently fell on hard times, partly through external (外部的) circumstances and partly through poor planning. Friends and I have loaned her money, paid her bills, given her food, and even tried to teach her budget techniques, but none of them has been a solution. She has just slipped deeper and deeper into financial trouble and depression.

    Last week she looked pale and unwell, very depressed and hopeless, very sad for a friend to see and I then thought about how the crown coin, a physical reminder of another's care and love had protected me, so I went to the bank for a $ 100 dollar-bill.

    I told my friend the story and asked her to keep the $ 100 in the back of her wallet. It turned out that she didn't have a wallet, so she put the money in a little pencil case where she kept her coins. She immediately felt better—"I feel rich, and thank you for being a good friend," she said, and we were both a bit teary.

    I went home and remembered a little wallet I had that I'd never used, and thought, "I'll give that to my friend." I opened it, and inside, found $ 100.

    So you're thinking about breaking up with me. But before doing that, make sure you have examined its short-term and long-term environmental effects.

    Let's start simple: consider the great number of gallons of clean, drinkable water that would be wasted by my crying in the shower. Scientists don't have a precise estimate of how much water might be lost, but, considering the length of my listening to the recent two sad albums during the shower, the amount is sure to be catastrophic.

    Make no mistake: running from my sweet hug leaves a set of carbon footprints. Your leaving me will start a swift chain of events that results in me at a bar, drunkenly cursing at you with my friends.

    At the end of the night, I will be forced to take a taxi home instead of the subway. Those extra carbon dioxide releases are a breakup by-product, as are the single-use plastic bottles of Glacier Freeze-flavor Gatorade I'll surely buy the next morning.

    Some effects are more hidden. Should you kick me to the roadside, you must anticipate that I am going to sit there eating ice cream. I will eat ice cream a lot every day, because I have seen sad women do this in movies. This, of course, causes ecological disaster. Not only do dairy cows produce greenhouse gas, but industrial dairy farming can cause the destruction of prairies (北美草原) forests, and other ecosystems. You might meet other interesting women in your life, but good luck is replacing North America's wetlands!

    Breaking up with me is a very personal choice, and no one can make it for you. I only hope that you have gained a helpful new way of thinking, one broad enough to deal with the world that waits for you in your single-hood. There might be "other fish in the sea," but will there be actual fish in the real sea? It doesn't look good. Alternatively, we could stay together and preserve this beautiful blue sea for our grandchildren. The Intergovernmental Panel on Climate Change and I eagerly wait for your decision.