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(A) After a few years of trial-and-error, it was decided that certain breeds are better guides than others.
(B) Efforts are made to build mutual understanding and to avoid any misbehavior that might be devastating.
(C) Located in Germany, the school was unusual because it was a school for dogs instead of humans.
(D) This is to get it exposed and accustomed to all kinds of situations it may encounter in the future.

The idea that dogs can act as eyes for those who are blind first developed at the beginning of the twentieth century in a unique school. 12 These dogs were trained to lead people who could not see. It was quickly discovered, however, that not every breed品種、繁殖 of dog was fit for the school. Being a guide dog requires the dog to be alert at all times, so dogs that are easily distracted使轉移注意力，干擾 are not suitable. 13 Breeds品種  such as Labrador retrievers拉布拉多, German shepherds德國牧羊犬, and boxers 拳師狗（中等大小的短毛狗）make excellent guides because they are friendly and easy to train.

During its training, the dog is taken to many kinds of busy places such as large stores, noisy airports, and crowded restaurants. 14 The dog must learn to ignore anything that might cause its attention to wander because it is responsible for steering操縱 its owner carefully past any obstacle. For example, the guide dog is trained to come to a stop just before it reaches a curb控制；限制 so as to爲了，以便 tell the owner to take a step up or down.

When training is finally finished, a guide dog is assigned分配 to an owner. The two of them must be compatible可共存的；協調 because they will be partners for a long time. 15 For example, a big and strongly built person will be more comfortable with a large dog while an indoor person will probably not want to be matched with a dog that needs plenty豐富，充足，大量 of exercise.