摘要
Dolphinsareveryinterestinganimals.Theylooklikefishbuttheyarenotfish.Fishhavecoldbloodbutdolphinshavewarmbloodlikeotheranimals.Fishcanliveunderwaterbutdolphinscannot.Theycanstayunderwaterforalongtimebutthentheyhavetocomeupbecausetheybreatheair.Fishlayeggsbutdolphinshavelivingbabies.Thesedrinktheirmother’smilklikeother
出版日期
1990年02月12日（中国期刊网平台首次上网日期，不代表论文的发表时间）
