很多考生在准备托福考试的时候，总会发现部分托福考试中的句子远远超出了自己的能力范围。对于这些长难句，当然要从语法的角度去完全把握。下面就让出国留学网小编带你去看看那些前辈们总结的方法吧。
其实长难句在考试中最直接的运用就是考察插入句子题和解释句子题。对于这样的题目，我们在不能读懂句子的情况下，能够把握的就是句子的内在关系，即逻辑。下面是托福阅读中经常出现的四大逻辑关系，把握了它们就等于掌握了托福阅读解题技巧的一个重要部分。
1. 因果关系
因：because, because of, for, as, since, in that, on account of, with
果：so, so that, therefore, thereby, as a result, hence, thus, consequently, accordingly
因果关系除了传统意义上的显性因果表达词外，隐性的因果同样是不可忽略的一个重要部分。
隐性因果：
A.导致(因-果)：cause, reason, lead to, give rise to, result in, render, make, let, ask, support, push, stimulate, spark, spur, fuel, produce, be responsible for
如The increased pressures of expanding populations have led to the removal of woody plants so that many cities and towns are surrounded by large areas completely lacking in trees and shrubs。
在这段话中，有lead to, 表示了导致的意思，即结果; 而so that 更进一步表示了后面的结果，所以可以充分判定这段话有因果关系的逻辑。
B.由…而来(果-因)：result from, derive from, originate from, initiate from, stem from, be responsive to, be attributable to
如 “The extreme seriousness of desertification results from the vast areas of land and tremendous numbers of people affected, as well as from the great difficulty of reversing or even slowing the process。”
在这段话中，根据result from可以推断出有因果关系，那如果是解释句子题时，选项中有因果关系就可以优先考虑。
C.反映，体现(果-因)： reflect, present, demonstrate, suggest, imply, show
This result demonstrates that…
D.考虑到： ...