在开始之前，我们先来用两道题复习一下上一篇讲到的省略非重点：
1. Escape involves such actions as aestivation, a condition of prolonged dormancy, or torpor, during which animals reduce their metabolic rate and body temperature during the hot season or during very dry spells.
○ One way animals escape is by entering a state of extended dormancy, known as aestivation, during the hottest and driest times of year.
○ Animals can escape without using direct action, or aestivation, simply by reducing their metabolic rate and body temperature.
○ The actions that an animal uses to escape are known as aestivation, which sometimes involves a reduction in metabolic rate or body temperature.
○ When the weather is especially hot and dry, an animal may suffer from a condition known as aestivation, at which point the animal needs to escape.
碰到这种同位语或插入语很多的情况，一定要以读懂为主，不要纠结生词!
2. Learning appropriate social behaviors is especially important and species that live in groups, like young monkeys that needed to learn to control selfishness and aggression and to understand the give-and-take involved in social groups. ( 举例论证)
A. Only monkeys that have learned to control their selfish and aggressive behaviors can be involved in social groups.
B. Selfish and aggressive animals like monkeys live in groups in order to practice appropriate social behaviors.
C. Some monkeys are naturally too selfish and aggressive to understand the give-and-take of social groups, so they learn such important behaviors while young.
D. Monkeys and other social animals need to learn behaviors appropriate for their social groups.
原句中，前面是论点后面是论据，学习合适的社会行为对群居物种很重要，举猴子的例子。
选项中，D选项猴子和其他群居动物需要学习behaviors，符合原句。 A选项only就错了，用论据代替了论点;B选项in order to前后反了，是因为要群居，所以才practice behaviors; C选项直接说some monkeys，跟A选项一样，用例子代替论点，而且说错了
除了直接的因果关系词之外，还有表示导致/归因于的词大家要非常关注!包括 be responsible for…, cause, lead to, give rise to…, contribute to…,result in等;以及表示explain的account for…。作者: 共惜年月 时间: 2017-2-7 18:10
一下子丢出这么些词可能有些无从下手，我们来看下具体的题目：
1. Because the medium was so prolific, in the sense that it was possible to produce a multitude of images very cheaply, it was soon treated as the poor relation of fine art, rather than its destined successor.
O Photography did not replace other fine arts because people felt the image looked cheap in relation to the other arts.
O Photography was so cheap and readily available that it could be purchased by people who were too poor to purchase fine art.
O Photography not only spread quickly but also was a cheap art form and so became true successor of fine arts rather than its poor relation.
O Photography was not considered a true art because people could use it to create many images cheaply.
原句中，because表示因果，因为the medium非常prolific，后面in the sense that (在某种意义上因为)进一步补充prolific，prolific是因为produce cheaply;所以它被当成art的穷亲戚，而非继承者(rather...than...表对比)。也就是说：因为medium便宜，所以多，所以不被当成fine art。
2. Importing the grain, which would have been expensive and time consuming for the Dutch to have produced themselves, kept the price of grain low and thus stimulated individual demand for other foodstuffs and consumer goods.
○ Buying imported grain led to the Dutch demanding that other foodstuffs and consumer goods be imported.
○ Keeping the price of grain low was a primary goal of the Dutch at a time when they could not produce enough grain to provide for all their needs.
○ The demand for other foodstuffs and consumer goods forced the Dutch to import grain and other products at a time when maintaining low prices was especially important.
○ Because the Dutch were able to import inexpensive grain, they had money available to create a demand for other food products and consumer goods.