某中子星的质量大约与太阳的质量相等，为2 ×10³⁰kg，但是它的半径只有10km，地球质量为6 ×10²⁴kg，地球半径为6400km，求：

（1）此中子星表面的重力加速度；

（2）沿中子星表面圆轨道运动的小卫星的线速度。

第二节：语法填空（共10小题，每小题1.5分，满分15分）

阅读下面短文，按照句子结构的语法性和上下文连贯的要求，在空格处填入一个适当的词或使用括号中词语的正确形式填空，并将答案填写在答题卡标号为31—40的相应位置上。

For many environmentalists, the world seems to be getting worse. They have developed a it-list of our main fears: natural resources are running out; the population  31  (grow), leaving less and less to eat; species are becoming  32  (extinction) in vast numbers, and the planet’s air and water are becoming dirty,  33  are ever more polluted.

34  a quick look at the facts shows a different picture. First, energy and other natural resources have become more abundant not less so. Second,  35  food is now at any time in history. Third, although species are indeed becoming extinct, only about 0.7% of them are expected   36  (disappear) in the next 50 years, not 25~50%, as has so often been predicted. And finally, most forms of environmental pollution   37  appear to have been predicted, or are too short– associated  38  the early stages of industrialization.   39  bigger problem may well turn out to be an inappropriate response to it. yet opinion polls suggest that many people develop the   40  (believer)that environmental standards are declining and some factors seem to cause this disjunction.