| 1. | Comment on the relation between this period and the period of a satellite revolving close to the surface of the earth .
解释这个周期和卫星沿接近地球表面的轨道旋转的周期之间的关系。 |
| 2. | As the nearest celestial body to our earth, the moon has, of course, always been a favored object for the amateur astronomer .
月球是最接近地球的天体，当然总是业余天文学家喜爱的对象。 |
| 3. | We can see comets only when they come close to the earth
只有当彗星接近地球时,我们才能看得见它们。 |
| 4. | We can see comet only when they come close to the earth
只有当彗星接近地球时，我们才能看得见它们。 |
| 5. | As the spacecraft came closer to the earth , it was put into its re - entry mode
宇宙船在接近地球的时候，采取了重返大气层的操作方式。 |
| 6. | The moon , being our only natural satellite , is the closest celestial body to the earth
月球，是人类唯一的天然卫星，亦是最接近地球的天体。 |
| 7. | A mars day is almothe same length as an earth day . a day on the moon is an earth month
火星的一天接近地球的一天，月球的一天是地球的一个月。 |
| 8. | The moon , being our only natural satellite , is the closest celestial body to the earth
月球，是人类唯一的天然卫星，亦是最接近地球的天体。 |
| 9. | It is the nearest star and is the only star that we can study in details
在天文学上，太阳是最接近地球的恒星，亦是唯一可以让人类详细研究的恒星。 |
| 10. | Future close approaches of mars to earth until 3000ad , in ascending order of distance
未来火星更接近地球的日期截至公元3000年，按距离由近至远排列 |
