【小站原创】官方真题Official42托福阅读文本及答案解析（Geographic Isolation of Species）
- 2016年05月10日10:48 来源：小站教育作者：小站托福编辑
- 参与（29） 阅读（43451）
在托福阅读的备考过程中，除了大量的阅读之外，全面了解托福阅读的题型和解题方法也都是非常重要的环节。那么，在以下内容中就为大家带来官方真题Official42中托福阅读文章题目及相关解析内容，希望能为大家的备考带来帮助。
Geographic Isolation of Species
(原文略)
paragraph 1
Biologist Ernst Mayr defined a species as “an actually or potentially interbreeding population that does not interbreed with other such populations when there is opportunity to do so.” A key event in the origin of many species is the separation of a population with its gene pool (all of the genes in a population at any one time) from other populations of the same species, thereby preventing population interbreeding. With its gene pool isolated, a separate population can follow its own evolutionary course. In the formation of many species, the initial isolation of a population seems to have been a geographic barrier. This mode of evolving new species is called allopatric speciation.
1. The word “key” in the passage is closest in meaning to 【词汇题】
A. early B. crucial C. noticeable D. frequent
答案：B
解析：key, 关键的。
Early, 早期的。Crucial, 重要的，决定性的。Noticeable, 显而易见的，值得注意的。Frequent, 频繁的。所以B选项正确。
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