托福阅读修辞目的题实例解析（五）

在托福阅读的十大题型中，修辞目的题(rhetorical purpose questions)是新托福阅读中难度较大的题型之一。这种题型对于国内考生来说较为陌生，在考场上时间紧张的情况下考生往往不知该在文中什么地方找答案。那么，对于这样一种类型的题目我们究竟该从何入手呢?在以下的一些例题中，我们就为大家进行详细的分析。

托福阅读修辞目的题例题

5. 判断该句是D还是TS:若是TS，读本句即可。

例题5：

Paragraph 4：There is still no universally agreed-on explanation for why there should be such a dramatic cessation of tree growth at the upper timberline. Various environmental factors may play a role. Too much snow, for example, can smother trees, and avalanches and snow creep can damage or destroy them. Late-lying snow reduces the effective growing season to the point where seedlings cannot establish themselves. Wind velocity also increases with altitude and may cause serious stress for trees, as is made evident by the deformed shapes at high altitudes. Some scientists have proposed that the presence of increasing levels of ultraviolet light with elevation may play a role, while browsing and grazing animals like the ibex may be another contributing factor. Probably the most important environmental factor is temperature, for if the growing season is too short and temperatures are too low, tree shoots and buds cannot mature sufficiently to survive the winter months.

Q:In paragraph 4, what is the author’s main purpose in the discussion of the dramatic cessation of tree growth at the upper timberline?

A:To argue that none of several environment factors that are believed to contribute to that phenomenon do in fact play a role in causing it.

To argue in support of one particular explanation of that phenomenon against several competing explanations.

To explain why the primary environmental factor responsible for that phenomenon has not yet been identified.

To present several environmental factors that may contribute to a satisfactory explanation of that phenomenon.

托福阅读修辞目的题练习题答案：4