A. H5N1 does not transmit among human beings B. bird flu spreads only among birds C. H5N1 is a variant of flu virus D. bird flu adapts easily to other species 参考答案:C 答案解析:此题考查对有关H5N1细节的理解。根据第三和第四段得知C)是答案。特别注意A),虽然最后一段提到no person-to-person transmissions have been reported