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　　Flu, or influenza, is a common illness that makes you feel very tired and weak, and makes you cough and have a fever．But recently we find a new kind flu c　1　　　 H1N1 influenza A．We find ourselves in the dark about the terrible flu virus．Is it quite d　　2　　 from a common flu? The answer is no, because it seems s　　3　　 to regular human flu with a fever, cough and a headache．The answer is y　4　　　, because it has caused at least 64 d　　5　　 around the world．And the World Health Organization has confirmed(确诊)about 6,500 cases．

　　The flu virus first appeared in pigs or swine．WHO says the virus is being spread from human-to-human, not from contact with infected(被感染的)pigs．Scientists try to know clearly how it jumped to humans．The steps are aimed at stopping further spread of the virus．

　　Pork imports(进口)aren’t a　　6　　 from the areas which have swine flu．Though experts said swine flu is not connected with pigs and not spread by e　　7　　 pork．

　　So far groups of illnesses seem related to Mexican(墨西哥)travel．For example, some students in New York fell i　　8　　 from an spring outing in Mexico．Flu viruses can be spread by touching(触摸)your mouth or nose w　　9　　 unwashed hands．Swine flu can be treated, but so many confirmed cases s　　10　　 that we had better take early notice, in case it would be too late．