| 1. | The spiral nebulae are impressive objects . 旋涡星云是迷人的天体。 |
| 2. | This suggest that the nebulas are aggregates of stars . 这说明星云是恒星的聚集体。 |
| 3. | A nebula is really a discrete mass of innumerous stars . 一团星云实际上是无数星体不连续的集合体。 |
| 4. | The element hydrogen comprises 90% of the matter in gaseous nebulae . 元素氢占气体星云物质的90。 |
| 5. | The element hydrogen comprises 90% of the matter in gaseous nebulae . 元素氢占气体星云物质的百分之九十。 |
| 6. | Galactic nebulas are masses of diffuse material within our galaxy . 银河星云是我们星系中的一团团弥散物。 |
| 7. | We have identified the crab nebula as the debris of this explosion . 我们已证明蟹状星云就是这次爆炸的遗迹。 |
| 8. | The investigation of dark nebulas has been facilitated by a new discovery . 对暗星云的研究被一种新发现所推进。 |
| 9. | The trifid nebula itself represents the final phase of star formation . 三叶星云本身代表着恒星形成的最后阶段。 |
| 10. | Many objections can be raised to this picture of planetary nebula formation . 形成行星状星云的这一图像可能会引起许多异议。 |