句子之间的关系多种多样，常见的有：并列关系、因果关系、递进关系、转折关系和相互解释关系。
Women could and did play a part in this process of settlement. Iceland, for instance, was uninhabited, and a permanent population could only be established if women also made the journey there. (后一句的具体事例为前一句提供说明与解释)
People borrowed more and more money so that they could buy these shares. Because of this, the American people started to believe that share prices could only go up further. (“because of”明显的因果关系)
Astronomy is a science that deals with all the celestial bodies in the universe. Astronomy includes the study of planets and their satellites, comets and meteors, stars and interstellar matter, star systems and clusters. (后一句是对前一句celestial bodies 的进一步解释)
Previously it was believed that due to the Archaeopteryx’s (始祖鸟) underdeveloped anatomy, it would not have been able to fly. However, research by the London Natural History Museum into its brain developed and that it had good vision and a good sense of balance — all the requirements for a creature to be able to fly. (“However”转折对比)
阅读时，我们可以根据段落中出现的一些信号词(Signal Words)来判断句子与句子之间的关系，掌握段落发展线索，来调整阅读速度，提高阅读质量。
1．显示相同信息的信号词：
There has been an upsurge of interest in chamber music. Likewise opera is receiving a boost from increased record sales.
“likewise”这一信号词显示了前面所提到的idea后面还要再一次出现。因此，阅读时见到这样的信号词无须放慢阅读速度。这样的信号词还包括：
and, furthermore, more, than, that, also, likewise, moreover, in addition, what is more, for instance, for example
2．显示思路转折的信号词：
I’d like to go but I’m too busy.
“but”前后是完全不同的信息描述，它向读者显示了作者的思路在这里有了转折。阅读时，碰到这样的信号词我们需放慢阅读速度，以准确获取作者真正想要说明的意思。这类信号词还有：
although, however, on the contrary, but, in spite of, otherwise, despite, nevertheless, yet
3．显示因果关系的信号词：
As a result of the pilots’ strike, all flights have had to be cancelled.
All flights have had to be cancelled as a result of the pilots’ strike.
所有航班被取消的原因是因为飞行员们的罢工；飞行员们的罢工导致了所有的航班不得不被取消。显示因果关系的信号词还有：
for, thus, because, for this reason, so, therefore, as, since, consequently
4．显示顺序的信号词：
Internet speeds communication between companies, among co-workers through video-conferences, and among other individuals. First, media companies use the Internet for online news, or to broadcast audio and video, including live radio and television programs, while individuals use the Internet for communication, entertainment, finding information, buying and selling goods and services. Second, the notion of distance disappears thanks to the Internet. People also enjoy instant messaging to exchange text messages or pictures in real time, with real-time video and sound. Finally, scientists and scholars use the Internet to perform research, distribute lecture notes or course materials to students, they communicate with colleagues, and can also publish papers and articles.
抓住了这样的信号词就把握住了作者叙述的顺序，也就分清了相对独立的论据。这样的信号词包括：
first, second, third, and so on, then, after, before, next, last, afterward, finally
5．表示结论/总结的信号词：
In conclusion, I would like to say how much I have enjoyed myself today.
词组“in conclusion”前面所提到的一些信息将在这里被归纳总结。读到带有这样的信号词或短语的句子时，应格外留心注意，它们往往会向我们提示相关段落的核心信息。表示结论或总结的信号词和短语还有：as a result, finally, therefore, accordingly, in short, thus, consequently, in conclusion, so, in brief, in a word |
