大学英语： But if the star is very large (much bigger than our sun)

　　4. But if the star is very large (much bigger than our sun) this process of shrinking may be so intense that a black hole results. (p2)

　　译：但如果星球很大(比我们的太阳还要大得多)，其收缩过程可能很剧烈，以致于产生了黑洞。

　　句子分析：这是一个if引导的条件状语从句，so…that表示如此…以致，是结果状语从句。

　　如：I'm so tired that I can even sleep on my way home.

　　5. Imagine the earth reduced to the size of a marble, but still having the same mass and a stronger gravitational pull, and you have some idea of the force of a black hole. (p2)

　　译：假想一下地球收缩到弹球儿那么大，但仍具有同样的质量和更强的吸引力，你就会对黑洞的力量又某种概念。

　　句子分析：该句的主要结构为imagine….and you ……事实上相当于if you imagine…, you will have some idea….. 这种句子结构在历年的考试中曾出现过。请记住：祈使句+ and + 陈述句= if引导的条件状语从句。如：Hurry up and you can catch the last train!

　　另外，该句还有两个定语成分reduced to the size of a marble和having the same mass and a stronger gravitational pull用来修饰the earth.前者为过去分词，而后者为现在分词。词组：

　　have some idea of sth对…有所了解

　　6. It is only recently that astronomers have begun specific research into black holes. (p3line13--14)

　　译：只是近来科学家才开始对黑洞进行具体的研究。

　　句子分析：本句的核心结构为it is…that的强调句型，强调时间状语only recently。词组：research into sth对…进行研究。