| 1. | A number of factors contribute to this . 对于此总可以归诸于许多因素。 |
| 2. | A number of houses were burnt down in the fire . 好些房子给烧毁了。 |
| 3. | Businesses operate in a number of environments . 商业的环境错综复杂。 |
| 4. | We have lived here quite a number of years . 我们在这儿住了好些年了。 |
| 5. | He has left a number of books with me . 他把好些书存放在我这儿了。 |
| 6. | Within this lie a number of cell organelles . 里面有许多细胞器。 |
| 7. | An engine lathe consists of a number of parts . 普通车床由若干部件组成。 |
| 8. | A number of birds are circling overhead . 很多鸟在头顶上空盘旋。 |
| 9. | Mutation are produced by a number of chemicals . 许多化学试剂能产生突变。 |
| 10. | We received a number of curious stares from . 过路人向我们投来好奇的目光。 |