3.对太阳与地球的关系的理解

太阳对地球的重要性是显而易见的，可以说没有太阳就没有地球上的-切，人类生存的地理环境中，有大气、水、生物等要素，这些要素本身和要素之间是在不断变化的，其根本动力就是太阳辐射。从能量的角度看问题，自然地理环境中大多数运动和变化，本质上就是太阳能如何分配、再分配和转移。因此，太阳辐射是太阳对地球最大、也是最重要的贡献。太阳辐射对地球的影响，其一是太阳辐射对地理环境形成和变化的影响。其二是太阳辐射对人们生产和生活的影响。这一知识与第二单元《大气的热状况》一节知识有着密切的联系，应引起注意。太阳辐射体现了日地关系的一个方面。

2.关于地球上存在生命的问题

这一内容比较好地反映了地球与其宇宙环境的关系。分析这一问题时，比较侧重分析地球本身的条件，除了地球本身的条件，宇宙环境对地球上生命现象的出现，也具有举足轻重的作用。教材从宇宙环境和地球本身两个方面，来说明地球存在生命物质的原因。分三点说明宇宙环境有利于地球上生命的出现；从地球在太阳系中的位置，以及地球的体积、质量、内部物质运动等方面分析了地球自身的原因。需要说明的是，生命的起源是一个相当复杂的问题，涉及许多学科领域。我们要注意与其他学科如政治、历史、生物的综合。

1.了解宇宙中的天体系统层次及地球的位置。

宇宙间的天体都在运动着。运动着的天体因互相吸引和互相绕转，而形成许多大小不同的天体系统。按大小规模和包含的关系分成不同的级别和层次。同学应注意掌握天体系统结构表并通过其来分析与天体系统有关的问题。

It is five years since I graduate from No. 3 High School. Last Saturday, the class that I was

on held a get-together, which took us a long time prepare. It was indeed not easy to get in the

touch with everybody and set a well time for all of us. We all enjoyed this precious day greatly,

remember the time we spent together and the people they were familiar with. It was a pity which

some of us were not present as they had gone to abroad for further studies, but they called back

or sent greeting card from different places.

10. You can do nothing but ________ yourself ________ him as you are connected by marriage.

Answer Sheet

Name___________　　 Class ____________　 Number ___________

9.　　　 Look at your bedroom--- what a mess! It needs ___________________.　

8.　　　 Larke was proud to have joined in the annual sports meeting for college students ____________________ his university.

7.　　　 Nothing remained of the city. Everything was ______________________ by the fire.

6.　　　 She _____________ one bird, but missed it. All the birds flew in all directions.