Do you know how it is when you see someone yawn and you start yawning too? Or how hard it is to be among people laughing and not laugh yourself? Well, apparently it's because we have mirror neurons (神经元）in our brains. Put simply, the existence of mirror neurons suggests that every time we see someone else do something, our brains imitate (模仿)it，whether or not we actually perform the same action. This explains a great deal about how we learn to smile, talk, walk, dance or play sports. But the idea goes further： mirror neurons not only appear to explain physical actions y they also tell us that there is a biological basis for the way we understand other people. Mirror neurons can undoubtedly be found all over our brains, but especially in the areas which relate to our ability to use languages, and to understand how other people feel. Researchers have found that mirror neurons relate strongly to language. A group of researchers discovered that if they gave people sentences to listen to ( for example ：'The hand took hold of the ball' ) , the same mirror neurons were triggered as when the action was actually performed (in this example, actually taking hold of a ball). Any problems with mirror neurons may well result in problems with behavior. Much researeh suggests that people with social and behavioral problems have mirror neurons which are not fully functioning. However, it is not yet known exactly how these discoveries might help find treatments for social disorders. Research into mirror neurons seems to provide us with ever more information concerning how humans behave and interact(互动）.Indeed, it may turn out to be the equivalent (相等物）for ncurosciencc of what Einstein's theory of relativity was for physics. And the next time you feel the urge to cough in the cinema when someone else does--well，perhaps you'll understand why. 小题1:Mirror neurons can explain . A．why we cry when we are hurt B．why we cough when we suffer from a cold C．why we smile when we see someone else smile D．why we yawn when we see someone else stay up late 小题2:The underlined word 'triggered' in the third paragraph probably means “ ” A．set off B．cut off C．built up D．broken up 小题3:We can learn from the passage that mirror neurons  . A．relate to human behavior and interaction B．control human physical actions and feelings C．result in bad behavior and social disorders D．determine our knowledge and language abilities 小题4:What is the passage mainly about? A．Ways to find mirror neurons. B．Problems of mirror neurons. C．Existence of mirror neurons. D．Functions of mirror neurons.