GRE阅读主题句应该如何理解

1. 判断句;

2. 概括文章将来结构。

比如一个句子：Your minds changed my attitude. 这句话中并没有情态动词和系动词，因此这句话自然不是判断句，也就不是主题句。但只要在这句话中加入一个正负褒贬词，即一个词表明作者的'态度或观点的词即是判断句了。比如，Your minds successfully changed my attitude即是判断句了。

另外，如果一个句子不是判断句，只要它能够概括文章将来结构，及文章后面会从哪几个方面来说明，也是主题句。比如，People are living longer now. 这句话一定不是主题句，而如果这句话是，People are living longer now since the improvement of food condition and the development of medical technology.这句话即是主题句了。因为它概括了文章后面会从哪几个方向来进行说明。

如果考生在新GRE阅读题中掌握好了主题句判断方法，很多文章便可以很快把握文章的结构框架，帮助后面文章的理解。

比如一篇文章的开头是，Mycorrhizal fungi infect more plants than do any other fungi and are necessary for many plants to thrive， but they have escaped widespread investigation until recently for two reasons. First， the symbiotic association is so well-balanced that the roots of host plants show no damage even when densely infected. Second， the fungi cannot as yet be cultivated in the absence of a living root.