It is not a secret {#blank#}1{#/blank#} trees are vital to our life. They provide us with food, wood and most {#blank#}2{#/blank#} (important), oxygen. Now there is one more thing we can add to this list—blocking out harmful bacteria from water.

    The discovery {#blank#}3{#/blank#} (make) by a team {#blank#}4{#/blank#} (consist) of scientists from the Massachusetts Institute of Technology (MIT) and high school students {#blank#}5{#/blank#} were seeking a natural water filter(过滤)—one that would help communities in developing countries that do not have {#blank#}6{#/blank#} (accessible) to modern water filter systems.

    The {#blank#}7{#/blank#} (research), led by Professor Rohit Karnik, decided to turn{#blank#}8{#/blank#} trees for help, because they could allow liquid to flow through, while blocking out air bubbles.

    They began by cutting 1.5-inch-wide sections of tree bark from the branches of a white pine tree. The people related then tested the wood's filtering ability by pouring water containing red dye particles of different sizes through. To their {#blank#}9{#/blank#} (amaze), they found that it was effective in trapping all the particles. Greatly {#blank#}10{#/blank#} (encourage), the team conducted another experiment, this time with water that contained bacteria. Sure enough, the sapwood held back 99% of the bacteria, allowing only 1% to flow through.

    My feelings about science have{#blank#}1{#/blank#} (complete) changed. More than one science teachers at my new school {#blank#}2{#/blank#} excellent and {#blank#}3{#/blank#} (friend) . The science{#blank#}4{#/blank#} (facility) are very good with laboratories that have all the{#blank#}5{#/blank#} (late) equipment. Our chemistry teacher takes us to public science lectures about four times{#blank#}6{#/blank#} term, {#blank#}7{#/blank#} are always interesting, because the lecturers are famous at their area of science. In the last 20 years, seven Canadian scientists{#blank#}8{#/blank#} (win) the Nobel Prize. Now{#blank#}9{#/blank#} I'm becoming more and more interested in is physics and I want to study it at university. But my parents are {#blank#}10{#/blank#} (astonish), as they always thought I would become an English teacher.

    At first, only people {#blank#}1{#/blank#}England spoke English. Later, people from England {#blank#}2{#/blank#} (voyage)to other parts of the world and {#blank#}3{#/blank#}that, English began to {#blank#}4{#/blank#} (speak) in many other countrieas. Today, {#blank#}5{#/blank#}people speak English as their{#blank#}6{#/blank#}, second or foreign language than ever before. Native English speakers can understand each other {#blank#}7{#/blank#}they don't speak {#blank#}8{#/blank#}same kind of English. All languages change when {#blank#}9{#/blank#} communicate with one another. So there are British English, American English, Australian English and so on. They all have their own identity. Maybe one day Chinese English{#blank#}10{#/blank#} (become) one of the world Englishes.

    In the United States, there were 222 people {#blank#}1{#/blank#}（report）to be billionaires（亿万富翁）in 2003. The {#blank#}2{#/blank#}（rich）of these is Bill Gates, worth at least $ 41 billion, who made his money{#blank#}3{#/blank#}starting the company Microsoft. Mr. Gates was only 21 years old{#blank#}4{#/blank#}he first helped{#blank#}5{#/blank#}（set up）the company in 1976. He was a billionaire by then. {#blank#}6{#/blank#}, there are still some other people who have made lots of money at even {#blank#}7{#/blank#}（young）ages. Other young people who have {#blank#}8{#/blank#}（strike）it rich include Jackie Cogan and Shirley Temple. Both of these child actors made over a million dollars {#blank#}9{#/blank#}（act）in movies before they were 14. But   the youngest billionaire is Albert von Thurn und Taxis of Germany, who, in 2001, inherited（继承）a billion dollars when he {#blank#}10{#/blank#}（turn）18!

    All our dreams have something to do{#blank#}1{#/blank#}our feelings, tears, longings, wishes, needs and memories. But something on the “outside” may affect{#blank#}2{#/blank#}we dream. If a person is hungry or tired or cold, his dream may include a feeling of this kind. If the blanket on your body has slipped off your bed, you may dream that you{#blank#}3{#/blank#}(sleep) or resting on the ice or snow. So the subject of your dream usually comes from something{#blank#}4{#/blank#}has an effect on you while you are sleeping (feeling of cold, a noise, etc.) and it may also use your past{#blank#}5{#/blank#}(experience) and the wishes and interests you have now.

    There are some scientists who have made {#blank#}6{#/blank#}special study of why we dream, what we dream and what those dreams mean. Their{#blank#}7{#/blank#}(explain) of dreams, though a bit reasonable, is not accepted by everyone, and it offers an interesting way of{#blank#}8{#/blank#}(deal) with the problem. They believe that dreams are{#blank#}9{#/blank#}(most) expressions of wishes that did not come true. In other words, a dream is a way of having your wishes{#blank#}10{#/blank#}(carry) out.

Ask Helpful Hannah

Dear Helpful Hannah,

    I've got a problem with my husband, Sam. He bought a smartphone a couple of months ago and he took it on our recent ski vacation to Colorado. It was a great trip except for one problem. He has a constant desire {#blank#}1{#/blank#} (check) for text messages; he checks his phone every five minutes! He's so addicted to it that he just can't stand the idea {#blank#}2{#/blank#} there may be an important text. He can't help {#blank#}3{#/blank#} (check) even at inappropriate times like when we are eating in a restaurant and I am talking to him! He behaves {#blank#}4{#/blank#} any small amount of boredom can make him feel the need to check his phone even when he knows he shouldn't. The temptation to see {#blank#}5{#/blank#} is contacting him is just too great. When I ask him to please put down the phone and stop {#blank#}6{#/blank#} (ignore) me, he says, "In a minute," but still checks to see if {#blank#}7{#/blank#} has posted something new on the Internet. Our life {#blank#}8{#/blank#} (interrupt). If we go somewhere and I ask him to leave the phone at home, he suffers from withdrawal symptoms. Maybe this dependency on his smartphone has become more than an everyday problem.

    I recently read an article about "nomophobia," {#blank#}9{#/blank#} is a real illness people can suffer from: the fear of being without your phone! I am worried that Sam may be suffering from this illness {#blank#}10{#/blank#} he feels anxious if he doesn't have his phone with him, even for a short time.

    Who would have thought that little devices like these could have brought so much trouble!

Sick and Tired Sadie