As we know, people who can't see anything live difficult lives. They may have(苦恼)in going out. Also, they feel (寂寞)when they stay at home alone. Can people save these problems?

    In 1918, a doctor and his pet dog walked with a (眼瞎的) soldier. The doctor had something to do in the hospital, so he left his pet dog and the soldier for a short time. When he came back, he (注意到)his pet dog guided the soldier safely. So he made a (决定)that he would teach dogs to guide persons and he succeeded at last. This made the people who can't see (兴奋的).

    The best dogs for the job are clever. It takes more than two years to (训练) a little dog to be a guide-dog. When the dog is 14 months old, it can understand people's instructions(指令) easily. Then it will meet its new  (主人)and they need to practice together for four weeks. With the help of the guide-dog, the disabled people become (独立). They never  (依靠)on others.