二、精选真题长难句演练

　　通过以下真题长句的演练分析，希望同学们熟知分析长难句的切入点，将长难句化繁为简地进行理解。

　　1. Research has found that IQ predicted leadership skills when the tests were given under low-stress conditions, but under high-stress conditions, IQ was negatively correlated with leadership—that is, it predicted opposite.

　　[解析]本句主干是Research has found that…, that引导的是宾语从句，直到句末。此宾语从句是由but连接的两个表示对比关系的并列分句组成，第一个分句的主干是IQ predicted leadership skills, 其后是条件状语从句when the tests were given under low-stress conditions; 第二个分句的主干是IQ was negatively correlated with leadership, 之前的介词结构under high-stress conditions作状语，是个省略结构，补充完整后应为when the tests were given under high-stress conditions。由that is(即，就是说)可知，破折号之后的句子是对前面主句的补充说明。

　　[参考译文]研究发现如果在压力小的时候测试，那么IQ结果就能预测出领导能力，但如果在压力大的时候测试，IQ结果就会与领导能力相反——也就是说，它的预测是相反的。

　　2. But science does provide us with the best available guide to the future, and it is critical that our nation and the world base important polices on the best judgments that science can provide concerning the future consequence of present actions.

　　[解析]本句是由and连接的两个并列分句组成，其中第一个分句较为简单，但要注意does的强调用法。第二个分句中it是形式主语，真正的主语是由that引导的主语从句that our nation and the world base important policies on the best judgments, 第二个由that引导的从句that science…of present actions是定语从句，修饰先行词judgments。

　　[参考译文]但是科学确实为我们提供了对未来的最可靠的指引。关键是我们的国家乃至全世界在做出重要决策时，应以科学能提供给我们的、关于人类现在行为对未来影响的最佳判断为依据。