| 1. | Mules are very useful animals 骡子是非常有用的动物。 |
| 2. | A horse is very useful animal 马是一种有用的动物。 |
| 3. | The horse is a useful animal 马是一种有用的动物。 |
| 4. | The cow is a useful animal 奶牛是有用的动物。 |
| 5. | A horse is a useful animal 马是有用的动物。 |
| 6. | The horse is a useful animal 马是有用的动物 |
| 7. | Many species are abundant enough to be utilised as a source of meat , skins , and other useful animal products 很多动物资源十分丰富,可以用来制作肉类、皮毛及其它有用的动物产品。 |
| 8. | The earthworm is a useful animal . on the ground it is food for other animals . under the ground , it makes rich soil for fields and gardens 蚯蚓是一种有益的动物。在地面上它是其他动物的食物。在地下,它为田园和花园制造肥沃的土壤。 |