| 1. | Suckling is an instinct in mammals .
哺乳是哺乳动物的本能。 |
| 2. | Other seed-eating mammals may become troublesome .
其它取食种子的哺乳类也会引起麻烦。 |
| 3. | A whale is a kind of mammal .
鲸是一种哺乳动物。 |
| 4. | Lactation is the final phase of the reproductive cycle of mammals .
泌乳是哺乳动物繁殖周期的最后阶段。 |
| 5. | Mammals damage orchards on every continent by girdling roots .
哺乳动物在各地对种子园的危害是咬断根系。 |
| 6. | Mammals arose from a fairly primitive reptile in the mesozoic era .
哺乳类起源于中生代宛若原始的爬虫类。 |
| 7. | He lists three types of steroid sex hormones that function in mammals .
他列举在哺乳动物中起作用的三种类固醇性激素。 |
| 8. | Fish and reptiles are more likely to change sex than are mammals or birds .
鱼和爬行动物一般要比哺乳动物或飞禽更容易改变性别。 |
| 9. | The main groups of vertebrates are: fishes, amphibians, reptiles, birds and mammals .
脊椎动物的主要种类是鱼类，两栖动物，爬行动物，鸟类和哺乳动物。 |
| 10. | Professor owen has subsequently extended the same generalization to the mammals of the old world .
以后欧文教授把这一法则引伸到“旧世界”的哺乳动物。 |
