A sick little gift is being kept alive thanks to her best friend--a dog who carries her oxygen tank on his back. Alida’s faithful dog companion Mr. Gibbs has been specially trained to shepherd the three-year-old, who breathes through a tube most of the time. He follows her closely as she plays in her family’s ten-acre land in Louisville, uses the slide or even rides her bike.
Alida was diagnosed（诊断）with neuroendocrine hyperplasia of infancy（NEHI）when she was just eight months old. Her rare condition has just eight hundred documented sufferers throughout the world, and causes diseased pieces of the lungs to filter（过滤）oxygen through extra layers（膜）of cells making it hard or almost impossible to breathe.
For Alida and her parents, it meant that even a walk in the park was very difficult because oxygen equipment was too heavy for the youngster to be able to carry herself. As parents they wanted to do something to help their daughter survive despite having a tube following her all the time. The couple found out about “service dogs” from a TV program and realized an animal trained to help the blind could be trained to help Alida. They finally found help in the shape of golden doodle—a retriever（寻回犬）crossed with a poodle-dog Mr. Gibbs. Now--thanks to trainer Ashleigh Kinsley—Alida and Mr. Gibbs love nothing more than playing and running around together with the dog acting as Alida’s life saver.
21. What is Mr. Gibbs?
A. A trained dog. B. A policeman. C. A doctor. D. A firefighter.
22. When did the doctor know Alicia caught the disease?
A. At her birth. B. At the age of eight.
C. Before she was one year old. D. When she was three years old.
23. The underlined part “the couple” in paragraph 3 refers to ________.
A. Alida’s classmates B. Alida’s parents C. Alida’s doctors D. Alida’s pets
24. How did Alicia keep alive?
A. By training her dog. B. By staying with her parents.
C. By playing with her fellows. D. By breathing through a tube.