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.

    Today, our class went to “The Fishery”, {#blank#}1{#/blank#} is a local fish store, because we are learning about fish: where they live and how they are different from people. Inside the store it was very dark, except for the bright lights on top of each tank. The girl {#blank#}2{#/blank#}(work) in the store told me that the lights are neon, and they are used to show off the bright colours of each fish. Under the lights, the fish were blue, purple, yellow, and green. They {#blank#}3{#/blank#}(look) so beautiful that I wanted to take all of them home.

    With a timid voice, the little boy greeted his father as he returned from work, "Daddy, how much do you make an hour?"

    Greatly {#blank#}1{#/blank#} (surprise), the father said, "Look, son, not even your mother knows that. Don't bother me now, I'm tired."

    "But Daddy, just tell me please! How much do you make an hour," the boy insisted.

    The father, {#blank#}2{#/blank#} (final) giving up, replied, "Twenty dollars per hour."

    "Okay, Daddy? Could you loan me ten dollars?" the boy asked.

    Showing his restlessness, the father yelled, "So that was the reason {#blank#}3{#/blank#} you asked how much I earn, right? Go to sleep and don't bother me any longer!"

    It was already dark and the father was thinking about what he {#blank#}4{#/blank#} (say) and was feeling guilty. Maybe he thought his son wanted to buy something. Finally, trying to ease {#blank#}5{#/blank#} (he) mind, the father went to his son's room.

    "Are you {#blank#}6{#/blank#} (sleep), son?" asked the father.

    "No, Daddy. Why?" replied the boy.

    "Here's the money you asked for {#blank#}7{#/blank#} (early)," the father said.

    "Thanks, Daddy!" replied the son happily, putting his hand under his pillow and removing some money. "Now I have enough! Now I have twenty dollars!" the boy said to his father, who was gazing at his son, confused {#blank#}8{#/blank#} what his son had just said.

    "Daddy, could you sell me one hour of your time?"

    Time is {#blank#}9{#/blank#} precious to spend it all on work! Appreciate your loved {#blank#}10{#/blank#} (one) and don't take them for granted.

    I had always considered acupuncture (针灸) old-fashioned. But the drama of my recent strange illness and recovery changed my mind {#blank#}1{#/blank#} (complete).

    Last month, after sleeping through a flight, I discovered I couldn't move my right arm and fingers. The doctors diagnosed me with neural (神经的) injury. I was scared. Luckily, Richard, an acupuncturist, offered {#blank#}2{#/blank#} (help) me.

    I started my acupuncture treatment. Dozens of tiny needles {#blank#}3{#/blank#} (insert) across my arm and fingers. I dared not move, because even a small change of position could cause a sharp pain. After a few days, I could move my fingers. Two weeks {#blank#}4{#/blank#} (go) by before I could eat a meal with chopsticks. Within a month, my arm and fingers were almost back to {#blank#}5{#/blank#} (they) normal functions.

    In that clinic, I made friends with many other patients and heard their {#blank#}6{#/blank#} (story). One lady, who became deaf two months ago, has recovered her hearing abilities. I was very surprised at {#blank#}7{#/blank#} magic these tiny needles are.

    Acupuncture originated in China 2,000 years ago. Essentially, it functions {#blank#}8{#/blank#} improving the smooth flow of life force energy, {#blank#}9{#/blank#} (know) in Chinese as "qi". Although acupuncture may not cure all illnesses, at least it creates a good starting point for a healthy body. I hope the {#blank#}10{#/blank#} (wise) of acupuncture will continue to bring health to more friends.

    Living a life with meaning and purpose is the key to improving your psychological well-being. Your purpose doesn't{#blank#}1{#/blank#}(necessary), have to involve changing the world or finding a career {#blank#}2{#/blank#}(devote) to helping others. Instead, you might make it your purpose to be kind every day.

    {#blank#}3{#/blank#}you feel like your life lacks purpose, don't worry. There are many ways you can find purpose in life and build a life that has more meanings. You can begin by thinking about the legacy(遗赠) you would like to leave behind. Write down how you'd like to {#blank#}4{#/blank#}(remember) at the end: of your life, or think about the impact you want to leave {#blank#}5{#/blank#}the planet. Then, establish some{#blank#}6{#/blank#}(objective)that can help you reach those goals. {#blank#}7{#/blank#}(work) toward your goals will give you a reason, to get out of bed every day, beyond earning money.

    Thinking positively{#blank#}8{#/blank#}(improve) your psychological well-being. In turn, as your psychological well-being improves,{#blank#}9{#/blank#} becomes easier to think positively and feel good overall. Spend time thinking about some of the best memories - of your life. Whether it's a family vacation you went on 10 years ago or you won an award at work two years ago, recalling the {#blank#}10{#/blank#}(happy) times in your life can bring more positivity to your thinking.