1. But if the animals are confronted with situations they have no control over, they later behave passively when faced with experiences they can control. (1999. 阅读. 6. Text 1)

【译文】但是如果动物面临它们自己无法控制的情况，那么此后它们在面对自己可以控制的情况时就会表现得消极。

【析句】复合句。主句是they later behave passively,主句前是if引导的条件状语从句，they have no control over作定语从句修饰situations。主句后面是when引导的省略了主语、系动词的时间状语从句，而时间状语从句中experiences后有they can control定语从句修饰。

2. In 1975 psychologist Robert Ader at the University of Rochester School of Medicine conditioned mice to avoid saccharin by simultaneously feeding them the sweetener and injecting them with a drug that while suppressing their immune systems caused stomach upsets. (1999. 阅读. 6. Text 1)

【译文】1975年罗彻斯特大学医学院的心理学家罗伯特·阿德在使小白鼠对排斥糖精形成条件反射的实验中，喂食老鼠的同时给它们注射一种抑制免疫系统还会引起腹痛的药剂。英语六级翻译

【析句】复合句。主句是Robert Ader conditioned mice to avoid saccharin by...。比较复杂的是by引导的方式状语，by feeding and injecting...,体现了介词后的动词要用ing形式。而inject them with a drug后that引导定语从句修饰a drug,并且定语从句中，that caused stomach upsets作主句，while引导时间状语从句。

3. In order to extinguish this dislike for the sweetener, Ader reexposed the animals to saccharin, this time without the drug, and was astonished to find that those mice that had received the highest amounts of sweetener during their earlier conditioning died. (1999. 阅读. 6. Text 1)

【译文】为了消除小白鼠对于糖精的排斥，阿德再次让小白鼠接触糖精，但这次不再注射药物。他惊讶地发现，那些在之前的条件反射训练中摄取糖精量最大的小白鼠都死了。

【析句】复合句。主句是Ader reexposed the animals to saccharin, and was astonished to find that..., 可以看出，主句由and连接的两个并列句组成，前一句为简单句，in order to extinguish...在第一句中作目的状语，this time without the drug作伴随状语。后一句中，find后有that引导的宾语从句，those mice died,而宾语从句的主语those mice后又有that引导的定语从句修饰。