大学英语：Well, it's difficult to answer this question

　1. Well, it's difficult to answer this question, since the terms we would normally use to describe a scientific phenomenon are inadequate here.(p1)

　　译：哦，这个问题很难回答，因为我们通常用来描述一种科学现象的现有术语在这里不够用。

　　句子分析：it是形式主语，to answer this question是句子主语;since引导原因状语从句，we would normally use to describe a scientific phenomenon是定语从句，修饰terms; inadequate: 不充分的，不合格的。

　　2. Astronomers and scientists think that a black hole is a region of space not a thing into which matter has fallen and from which nothing can escape---not even light. (p1)

　　译：天文学家和科学家认为黑洞是一个空间区域，而不是一个物体，物质会掉进黑洞而没有物体可以从中逃脱出来，即使是光也不行。

　　句子分析：into which和from which引导两个定语从句，介词：into和fall搭配;from 和escape搭配。这种介词+which的定语从句的形式请多注意。

　　3. The theory is that some stars explode when their density increases to a particular point. (p2)

　　译：(关于黑洞形成的)理论就是一些星球的密度增长到某个特定的点就会爆炸。

　　句子分析：这是一个主系表结构句。that用来引导表语从句，不可省略。其中又包含一个when引导的时间状语从句。to a particular point是达到某一个特定的点的含义。