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回答题Your dog is as smart as any two year old，according to a new study．Dogs bring much happiness to their owners．and even improve human health．Most two year olds keep us busy in life—an important part of living a long and happy life．According to Stanley Coren，Ph．D．of the University of British Columbia，our dogs are smarter than we thought．
Dr．Coren reviewed many studies to find out that dogs are as smart as 2 to 2．5 year olds．For—get about one word orders--according to Coren，the smartest dogs can learn up to 250 words．Most dogs understand an average of l65 words．“The upper limit of dogs ability to learn language is partly based on a study of a Border Collie(博得牧羊犬)named Rico who showed knowledge of 200 spoken words，and fast—track learning’，which scientists believed to be found only in humans and language．1earning apes(猿)．”
Dogs are also great at trickin9．During play，they have the ability to trick humans and other dogs in order to get treats．“And they are nearly as successful in tricking humans as humans are m tricking dogs，”says Coren．
Dogs can also count to four or five，which might explain how they know when their toys are missing．Coren explains，“Their astonishing flashes of smartness and creativity(创造力)are re—minders that they may not be Einsteins，but are sure closer to humans than we thought．”
Animals can do much to keep US happy，healthy，and protect tlS from harm．Stories of dog he-roes can be found using a simple Internet search．Pets teach US sense of duty，keep US from loneliness．and can help with treatment of the disabled．Dogs are smarter than we thought as smart as a two year old．
How do dogs bring happiness and health to humans according to the author? A．By doing funny tricks．
B．By keeping humans busy.
C．By serving their owners．
D．By playing with their owners.
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