在上课的过程中，经常发现同学们在某些题目当中发现不了对立，或者说反复出现的矛盾大家总是浪费时间在其他无意义的线索上，所以今天就这一点跟大家稍微聊一聊，说说GRE填空题目里面常遇到的一些概念比较，帮助大家节省时间精力，做题又快又准确。

来源：新东方 王灿

　　入侵物种/本地物种

　　题目当中一旦提到物种，基本就以入侵物种为主，而它的表达方式是初次接触GRE的同学不熟悉的。我们一起来看一看大家会在题目和选项当中碰到的种种“入侵物种”的说法：

　　invasive species = exotic species = introduced species = non-indigenous species = non-native species

　　题目当中，大家牢记，“入侵物种”的对立面只有一个，就是“本地物种”：

　　local species = native species = endemic species = non-introduced species = indigenous species

　　记住这两个概念的种种表达形式，大家能够快速准确的完成题目，避免GRE填空题目当中大量无用信息的干扰，这里给大家简单地举两个题目↓：

　　1.1 Origin, distribution, and habitat are included in the book for some but not all of the plants; offering this information for each species would have given readers a clearer appreciation of the differences between ______ and introduced species.

　　A. endemic

　　B. native

　　C. seasonal

　　D. rare

　　E. unusual

　　F. dominant

　　此题当中弄懂刚才讲解的概念的同学应该发现了这道题目当中真正有价值的信息只有最后的几个单词：differences between ______ and introduced species。其实题目就是问大家introduced species的反面是什么，“入侵物种”的反面就是“本地物种”，答案为AB。

　　下面的一道题同学们自己完成：

　　1.2 Although one can adduce myriad examples of ecosystem disruption by non-indigenous species, nevertheless most introduced species that survive in fact appear to have quite ______ effects on the ecosystems they have invaded.

　　A. minimal

　　B. trifling

　　C. marked

　　D. conspicuous

　　E. intriguing

　　F. deleterious

　　这里考到了“入侵物种”的两个表达方式(我以加粗形式给同学们表现出来了)，必须将这二者划上等号这个句子才完整，才有逻辑。答案为AB，请大家自行思考。