64、Rothschild might have concluded that ichthyosaurs(鱼龙) ______ .
A:failed to evolve an anti-decompression means
B:gradually developed measures against the bends
C:died out because of large sharks and crocodiles
D:evolved an anti-decompression means but soon lost it
请标准翻译题目及ABCD四个选项,谢谢