例句與造句

1. The evolution of erect limbs in mammals is incomplete  living and fossil monotremes have sprawling limbs.
2. In a further reappraisal, the molars of embryonic and fossil monotremes ( living monotreme adults are toothless ) appear to demonstrate an ancestral pattern of cusps which is similar to the triangular arrangement observed in therians.
3. In 1991, a fossil tooth of a 61-million-year-old platypus was found in southern Argentina ( since named " Monotrematum ", though it is now considered to be an " Obdurodon " species ) . ( See fossil monotremes below . ) Molecular clock and fossil dating give a wide range of dates for the split between echidnas and platypuses, with one survey putting the split at 19 48 million years ago, but another putting it at 17 89 million years ago.
4. It's difficult to find fossil monotremes in a sentence. 用fossil monotremes造句挺難的