When I was 13 years old, a boy gave me an important gift. It was a smile.
     It was the early autumn of my first year at a junior high school, and my old school was far away. As a
result, no one knew who I was. I was very lonely, and afraid to make friends with anyone.
     Every time I heard the other students talking and laughing, I felt my heart break. I couldn't talk to
anyone about my problem, and I didn't want my parents to worry about me.
     Then one day, my classmates talked happily with their friends, but I sat at my desk unhappily as usual.
At that moment, a boy entered the classroom. I didn't know who he was. He passed me and then turned
back. He looked at me and, without a word, smiled.
     Suddenly, I felt the touch of something bright and friendly. It made me feel happy, lively and warm.
     That smile changed my life. I started to talk with the other students and made friends. Day by day, I
became closer to everyone in my class. The boy with the lucky smile has become my best friend now.
     One day, I asked him why he smiled, but he couldn't remember smiling at me!
It doesn't matter because all the dark days have gone. Now I believe that the world is what you think it is.
If you think you are lonely, you might always be alone. So smile at the world and it will smile back.

1. Why was the smile an important gift?

A. The writer's old school was far away.
B. It made the writer feel happy, lively and warm.
C. The writer didn't know who the boy was.
D. The smile didn't mean anything to the writer.

2. Why do you think the boy smiled?

A. He was happy to see his friends.
B. He saw the writer was unhappy.
C. He really liked the writer.
D. He was a very friendly boy and smiled at everyone.

3. How did the smile change her life?

A. She began to make new friends.
B. She became best friends with the boy.
C. Her parents didn't worry about her any more.
D. She realized that it's important to smile at people.

4. Where does she now think her feeling of unhappiness came from?

A. From her old school.
B. From herself.
C. From other people in the world.
D. From the children at the new school.

     "Track!" said my master.
     Like any good tracker-dog who has received the command(命令)he most loves, I gave a bark
of excitement, put my nose down to the ground and sniffed. The ground was rich with smells. Even
in the high-class housing area where we were working, the stones held traces of many soft and
confusing scents (smells). As I searched for the scent that would give me a clue to the tail of the
guilty man, my tail wagged slowly, thoughtfully, delightedly. Work was like play to me; I enjoyed it.
     A small group of people gathered behind us. Among these onlookers was the old caretaker of
the building next door to ours. He spoke in a scornful voice, "You actually think your dog might catch
a thief three days after the event?" My master said nothing, but I'm sure he must have smiled. I did
not turn to look. I knew he would not speak unless it was to give me a new command.
     I needed to concentrate. My task was difficult. I had to pick out one scent among the many that
lay about and then tracked it to its source.
     "You're wasting your time," said the caretaker. I looked at him without raising my head. He was
running his hand over his fat stomach. His rough palm and smooth shirt combined to make a slight
noise. It was part of my training to be aware-often it is only a little whisper of a noise that alerts(提醒)
you to be drawing of a weapon. But of course the aging caretaker was going to do no such thing.
There was no smell of fear or nervousness about him. He was merely being clever and talkative.
     "I've seen many tracker-dogs in my time," said the caretaker to the onlookers. "I served with
the police years ago. We would never have thought of using a tracker-dog to find a car thief.
Impossible. Everyone knows that dogs are useless in such matters."
     In a sense he was right. I'm sure there's no need to tell you that, just as a dog's hearing is much
better than a human being's, so his sense of smell tells one thing from another far better than a great
detective. If Sherlock Holmes could work out that a man had had an egg for breakfast by seeing the
yellow stain on his mouth, a trained dog could tell you whether the hen that laid the egg was healthy
or not.
     I know it sounds funny and I mean it to be. But I'm not exaggerating. A dog can tell you-if you
understand a dog's way of communicating-all this and more without even setting eyes on the man he
is investigating.

1. Who do you think the dog was tracking?

A. The thief.
B. The caretaker.
C. The master.
D. The onlookers.