Animals perform many useful andentertaining jobs. Dogs are particularly valuable in guiding the blind,protecting property, finding lost people, and hunting down criminals. Horsesare used in guarding herds; carrying men in lands where there are no roads, andhelping farmers work their land. Pigeons have long been used to carry messages.Wild animals from the jungles, forests and seas are very popular performers incircuses and movies. People realize that, although animals may not have thesame intelligence as human beings, they are smart enough to learn certainthings. Dogs are extremely useful as companionsfor blind people. When dog has been properly trained, he will always lead his blindmaster in the right direction and keep him out of danger. For exampleseeing-eye dogs learn never to cross a busy road when cars are coming, even iftheir masters command them to do so. Horses are also able to learn many thingstoo. Horses that are used for guard or police duty must learn never to befrightened of noises, traffic, and other disturbance. Racing horses are able torun much faster than other horses, but they are also quite high strung.Therefore, it is necessary for people who train them to be very patient andunderstanding. Pigeons have a natural instinct to returnhome, even if they are very far away and the trip is hard or dangerous. Menutilize this homing instinct to send messages on small pieces of paper that arefastened to the pigeon's back or legs. In wartime, pigeons have been known tofly as fast as 75 miles an hour and to cover distances of 500 to 600 miles.These homing pigeons begin their training when they are about four weeks old.After a few weeks they can begin flying and carrying messages. If all goeswell, their flying career lasts about four years. Animals can learn to do many things that,while not necessarily useful, are very amusing to watch. In circuses, animalsare taught to do the tricks that are most compatible with their physical andtemperamental make-up. Lions and tigers can be taught to leap and springgracefully when told to do so, or to stay in place on command. Elephants learnto walk in line, to stand on their hind legs, to lie on their sides, and tostand on their head. They can also learn to dance.
something that interrupts (Para. 3)
【正确答案】：disturbance
