1. This is a difficult and unpleasant business and few animals would survive if they had to start from the beginning and learn about the world wholly by trial and error, for there are the have possible decisions which would prove fatal. (1992. 阅读. 6. Text 2)

【译文】这是个困难而又糟糕的事，因为如果动物出生后不得不从头学习生存本领，并且仅仅依靠尝试错误体验世界，那么只有极少数动物能够存活，因为它们做出的决定有可能是致命的。

【析句】复合句。主句由and连接两个并列句子组成，This is a difficult and unpleasant business and few animals would survive, and前的句子是简单句，and后的句子后又跟有if引导的条件状语从句和for引导的原因状语从句for there are decisions,decisions又有which引导的定语从句修饰。

2. Vigorous criticism is constructive in science more than in some other areas of human endeavor because in it there are adequate standards of validity which can be agreed upon by competent scientists the world over.(1992. 阅读. 6. Text 3)英语六级分数线

【译文】激烈的批评在科学界比在其他人类智慧领域更能起到建设性的作用，这是因为在科学世界里有足够多的有效标准，这些标准被全世界的优秀科学家们共同认可。

【析句】复合句。主句Vigorous criticism is constructive in science more than in some other areas of human endeavor,句中主要包含了比较级，具体是介词短语的比较级。主句后是原因状语从句because there are adequate standards of validity,定语从句which can be agreed upon by...修饰standards of validity。

3. He’s a historian of science at Massachusetts Institute of Technology who has discovered something else these two men-and, indeed, most of the major pioneers in science over the last 400 years-have in common: they were, like Sulloway himself, preceded in birth by at least one other brother or sister. (1992. 阅读. 6. Text 4)

【译文】他是麻省理工学院的一名科学历史学家，他发现了这两位科学家——实际上也是过去400年里多数科学界领军人物的共同点：那些人和Sulloway自己一样都至少由一个哥哥或姐姐。

【析句】复合句。主句He's a historian of science at MIT，后面是定语从句who has discovered something else,these two men-...-have in common是省略了关系代词that的定语从句修饰something else,破折号内的内容and most of the major pioneers...作插入语。最后，引号后的句子是something else的具体内容。