解释题

解释题的解题要领就一个：题目问什么，我们就回答什么。

通常来说，解释题有两种形式。

1. 问题让我们去explain或者justify文段中提到的一个现象。例如：

In areas with limited access to motorized transportation, farmers plant crops as close as possible to their homes to minimize the walking required to reach their fields and the work required to transport their harvest back to their homes. Farmers have almost no motorized transportation in certain parts of Africa where cassava is an important food crop. Although by no means the easiest to transport, cassava is invariably the crop planted farthest from these farmers' villages.

Which of the following, if true, provides the best explanation for the relative placement of the cassava crops?

2. 在文段的最后，会写：since/because ______.

以填空的形式让我们解释since/because前描述的现象。例如：

Which of the following most logically completes the passage?

A certain tropical island received food donations in the form of powdered milk for distribution to its poorest residents, who were thought to be malnourished.  Subsequently, the rate of liver cancers among those islanders increased sharply.  The donated milk was probably to blame:  recent laboratory research on rats has shown that rats briefly exposed to the substance aflatoxin tend to develop liver cancer when fed casein, a milk protein.  This result is relevant because __________.

我们在解题的时候，只要能准确找到并理解要解释的对象（现象）是什么，就不难选出正确答案。