3 因果关系
　　解题技巧：因果关系可以又表示原因、目的、条件、并列的词来表示，也可以没有关系词，是隐含的因果关系。
　　练习：
　　….An educated mother, on the other hand, has greater earning abilities outside the home and faces an entirely different set of choices. She is likely to have fewer but healthier children and can insist on the development of all her children, ensuring that her daughters are given a fair chance. The education of her daughters then makes it much more likely that the next generation of girls, as well as of boys, will be educated and healthy. The vicious circle is thus transformed into a virtuous circle…
　　Q: The author believes that a vicious circle can turn into a virtuous circle when _______.
　　A. women care more about education
　　B. parents can afford their daughters’ education
　　C. girls can gain equal access to education
　　D. a family has fewer but healthier children
　　答案：选C。原文倒数第二句提到，如果女孩拥有了平等受教育的机会，将来她的女儿受教育的机会就会更大，这样一代一代便形成了良性循环。原文中的thus明确表明了这种关系。选项中的gain equal access to对应文中的are given a fair chance。