面对这个问题：

It can be inferred from the passage that the first two generations of landscape photographers in the western United States had which of the following in common? 

你会不会到文章中去找题干中的关键词 the first two generations？

令你失望的是，文章中不会有 the first two generations 的。当然，也很可能并不会被你找到“first”的直接同义词（注意：无处可寻的是“直接”同义词。所以，你要小心“间接”同义词，通常是词义不直接完全对等，却在设定好的语境下表达了同样的概念）。

然而，你会在文章中找到这段话：

Western American landscape photography grew out of a male tradition, pioneered by photographers attached to government and commercial survey teams that went west in the 1860’s and 1870’s. These explorer-photographers documented the West that their employers wanted to see: an exotic and majestic land shaped by awesome natural forces, unpopulated and ready for American settlement. The next generation of male photographers, represented by Ansel Adams and Eliot Porter, often worked with conservationist groups rather than government agencies or commercial companies, but they nonetheless preserved the “heroic” style and maintained the role of respectful outsider peering with reverence at a fragile natural world. 

不知道你是不是立即找到了两个“generations of landscape photographers”。但是，你一定是立刻找到了“The next generation …”。于是，你已经锁定了其中一个“generation”，并且可以判断出另一个应该是在他们前面。于是，你可能找到前面的“These explorer-photographers”作为“pioneer”（是不是就是题干中的“first”？）的存在。那么，the first two generations 是不是就以“1+1=2”的方式出现了？

接下来，我们看一道“2+1=3”的算术题：

Biologists have long maintained that two groups of pinnipeds, sea lions and walruses, are descended from a terrestrial bearlike animal, whereas the remaining group, seals, shares an ancestor with weasels. But the recent discovery of detailed similarities in the skeletal structure of the flippers in all three groups …

你应该不会读到“in all three groups”突然懵圈了吧？毕竟“two groups of pinnipeds”加上“the remaining group”就是“all three groups”，这种简单的算术你一定会算。

看到这里，你可能觉得，这两个例子所表明的情况不是算术，而是一种语言表达中常见的现象：指代。其实，你的感觉没错。的确如此。那么，你也许就很期待我们的下一讲：

【如何通过搞清楚GRE阅读中的指代来读懂GRE阅读的文章】