阅读短文，从每题所给的四个选项（A、B、C和D）中，选出最佳选项。

    Some of the greatest problems we face today are the destruction (破坏) of our environment． Brown clouds, polluted water, endangered wild animals．．, these problems seem so huge．

    So my family does what we can． We take cloth bags to stores instead of using plastic bags． We walk where we don't have to drive．．．

    But does it do any good? When I am the only one in line at the market with cloth bags, am I doing any good? Does my walking to stores make any real difference to the world?

    I recently learned something about flamingos (火烈鸟) which like to get together in groups of a thousand or more． Every year, when the time comes for migration (迁徙), a few of them first takeoff from the lake． But none of the others seem to notice, so the small group returns．

    However, the next day they try again． This time few more fly along with them, but most of them still pay no attention, so they return again． They try for several times． Every time a few more birds join in but, since the thousands of others still take no notice, the great migration plan is once more stopped．

    Then one day something changes． The same small group of birds once again starts flying and a small number more join in just as before, then more． Finally, they all take flight and the migration really begins．

    What a spectacular sight it must be—thousands of flamingos taking off into the sky at once!

    A few can make a difference． Even if you're the one to take the first step, and continue trying, others will someday take notice and together we will solve even our greatest problems．

    Some years ago on a hot summer day in South Florida a little boy decided to go for a swim in the old swimming lake behind his house.

In a hurry to dive into the cool water, he ran out the back door, leaving behind his shoes, socks, and shirt as he went. He flew into the water, not realizing that as he swam towards the middles of the lake, an alligator(鳄鱼) was swimming towards the shore.

    His mother in the house was looking out the window and saw the two as they got closer and closer. In extreme fear, she ran towards the water, yelling to her son as loudly as she could. Hearing her voice, the little boy became alarmed and made a U-turn to swim to his mother. It was too late. Just as he reached her, the alligator reached him.

    From the dock, the mother grabbed her little boy by the arms just as the alligator snatched(夺取) his legs. That began an incredible tug-of-war(拔河). The alligator was much stronger than the mother, but the mother was much too passionate. A farmer happened to drive by, took aim and shot the alligator.

    After weeks and weeks in the hospital, the little boy survived. The newspaper reporter asked if he would show him his scars(伤疤). The boy lifted his legs, then, with obvious pride, he said to the reporter, "But look at my arms. I have great scars on my arms, too. T have them because my mum wouldn't let go."

    Some scars are unsightly and have caused us deep regret. But, some wounds are because love has refused to let go.

    Studies have shown it takes a doctor about 18 seconds to stop a patient after he begins talking.

    It was Sunday. I had one last patient to see. I came close to her room in a hurry and stood at the doorway. She was an older woman, sitting at the edge of the bed, trying to put socks on her swollen feet. I spoke quickly to the nurse, saw her chart saying she was in stable condition. I was almost in the clear.

    She asked if I could help put on her socks. Instead, I began a long speech that went something like this: "How are you feeling? Your blood sugar and blood pressure were high but they're better today. The nurse said you can't wait to see your son who's visiting you today. It's nice to have family visit from far away. I'm sure you really look forward to seeing him."

    She stopped me with a serious voice. "Sit down, doctor. This is my story, not your story."

    I was surprised and ashamed. I sat down. I helped her with the socks. She began to tell me that her only son lived around the corner from her, but she had not seen him in five years. She believed that the pressure of this caused greatly to her health problems. After hearing her story and putting on her socks, I asked if there was anything else I could do for her. She shook her head and smiled. All she wanted me to do was to listen.

    Listening to someone's story costs less than expensive diagnostic testing but is key to healing. I often thought of what that woman taught me—the importance of stopping, sitting down and truly listening. And, not long after, unexpectedly, I became the patient, with a diagnosis of sclerosis at age 31. Now, 20 years later, I sit all the time—in a wheelchair.

    For as long as I could, I continued to see patients from my chair, but I had to give up my job when my hands were influenced. I still teach medical students and other health care professionals, but now from the view of doctor and patient.

    I tell them I believe in the power of listening. I tell them I know firsthand that huge healing takes place within me when someone stops, sits down and listens to my story.

    There is a girl called Molly Whipple. She lives with her parents and two elder sisters, Polly and Dolly. Molly looks young for her age. Polly and Dolly sometimes laugh at(嘲笑) her, because she is so little. One day, the three sisters get lost in the woods(森林).

    "We're lost! We're lost!" Polly cries. "We'll never find our way home!"Dolly cries. But Molly says, "Of course we will. Look, there's a house. __▲__ "

    The house is very big. Who lives there? Molly knocks on the door. An old woman comes out. "Can I help you?" she asks. "I hope so, " says Molly. "We are lost. Would you please help us find our way home?" "Of course," says the old woman. "Come in and sit down. When my husband gets back, he will take you home. He loves children."

    The old woman closes the door. Molly finds a huge (巨大的) plate on the table and a huge pot(壶) on the stove(火炉). "Polly, Dolly…" Molly takes their hands. "I think we have to make our own way home."