TPO3托福阅读词汇真题练习：guarantee&ensure

在托福阅读备考过程中，词汇题是阅读题中必考的一个部分，而想要成功答对所有词汇题，并非仅从词汇量一个方面入手就可以。那么，在以下方面，我们就为大家带来一些TPO中的经典词汇题，大家不妨来练习一下吧。
Paragraph 5: Even the kind of stability defined as simple lack of change is not always associated with maximum diversity. At least in temperate zones, maximum diversity is often found in mid-successional stages, not in the climax community. Once a redwood forest matures, for example, the kinds of species and the number of individuals growing on the forest floor are reduced. In general, diversity, by itself, does not ensure stability. Mathematical models of ecosystems likewise suggest that diversity does not guarantee ecosystem stability—just the opposite, in fact. A more complicated system is, in general, more likely than a simple system to break down. A fifteen-speed racing bicycle is more likely to break down than a child’s tricycle. 【TPO3- The Long-Term Stability of Ecosystems】

8. The word “guarantee” in the passage is closest in meaning to

○increase

○ensure

○favor

○complicate

答案：(2)