Like a bird, Archaeopteryx had feathered wings. But it also had a cumbersome bony tail and lacked the large breastbone (and therefore the wing --- powering mass of muscle on its chest) that are characteristic avian traits, Milner said. 我怎么旧弄不明白,Archaeopteryx也有cumbersome bony tail? 和鸟一样? 太混乱了,这到题是问 cumbersome 和鸟有什么不同