打蛇打七寸 — 寻找逻辑词
何谓逻辑词？即because， therefore， nevertheless， in contrast…，但我们在否定事实题里找的不是它们而是 to begin with， and， furthermore， in addition， last but not least， finally。因为这类词的每一次出现通常对应的就是一个选项。例如：
TPO 21 The Origins of Agriculture
Paragraph 1： How did it come about that farming developed independently in a number of world centers （the Southeast Asian mainland， Southwest Asia， Central America， lowland and highland South America， and equatorial Africa） at more or less the same time？ Agriculture developed slowly among populations that had an extensive knowledge of plants and animals. Changing from hunting and gathering to agriculture had no immediate advantages. To start with， it forced the population to abandon the nomad＇s life and become sedentary， to develop methods of storage and， often， systems of irrigation. While hunter-gatherers always had the option of moving elsewhere when the resources were exhausted， this became more difficult with farming. Furthermore， as the archaeological record shows， the state of health of agriculturalists was worse than that of their contemporary hunter-gatherers.
2. According to paragraph 1， all of the following are advantages of hunting and gathering over agriculture EXCEPT：
A. It is a healthier lifestyle.
B. It requires less knowledge of plants and animals.
C. It does not need storage capabilities.
D. It is not tied to any specific location.
读完题目后，同学们在回看文章的时候都应该注意到 to start with， furthermore 这类逻辑联系词。
同时，我们观察到 to start with 之前的 Changing from hunting and gathering to agriculture had no immediate advantages 和题目所问的是相同的，所以就能基本确定答案是从 to start with 后面去找，只是题目问的是hunting和gathering 的好，而文章说的是从狩猎变成农业后的不好。我们只需把选项的意思反过来理解即可。
to start with 后面说的是农业让人们放弃游牧（nomad）变成一种不动（sedentary）并且需要发展储存食物的生活，反过来意味着hunting and gathering是不需要这样的。所以排除C，D选项。
Furthermore 后面说农业人的健康状况要比游牧的差，也就是后者生活的更优越。排除A。所以这题选B，即使它在原文出现，我们也不需要理会。因为 to start with 能告诉我们答案是从这里开始。
TPO 22 The Allende Meteorite
Paragraph 4： Equally perplexing constituents of Allende are the refractory inclusions： irregular white masses that tend to be larger than chondrules. They are composed of minerals uncommon on Earth， all rich in calcium， aluminum， and titanium， the most refractory （resistant to melting） of the major elements in the nebula. The same minerals that occur in refractory inclusions are believed to be the earliest-formed substances to have condensed out of the solar nebula. However， studies of the textures of inclusions reveal that the order in which the minerals appeared in the inclusions varies from inclusion to inclusion， and often does not match the theoretical condensation sequence for those metals.
7. According to paragraph 4， all of the following are true about the minerals found in the refractory inclusions EXCEPT：
A. These minerals are among the most resistant to melting of all the major elements in the solar nebula.
B. These minerals are believed to be some of the first elements to have condensed out of the solar nebula.
C. These minerals are among the least commonly found elements on Earth.
D. These elements occur in the order that scientists would have predicted.
我们细心阅读和比较后，也会发现这题的四个选项都在文章里出现，但是D选项“元素出现顺序和科学家预测一致”明显和原文最后一句的 often does not match the theoretical condensation sequence 矛盾。所以此题答案为D。
TPO28 Early Saharan Pastoralists
Paragraph 5： The cattle herders had only a few possessions： unsophisticated pots and polished adzes. They also hunted with bow and arrow. The Saharan people left a remarkable record of their lives painted on the walls of caves deep in the desert. Their artistic endeavors have been preserved in paintings of wild animals， cattle， goats， humans， and scenes of daily life that extend back perhaps to 5，000 B.C.. The widespread distribution of pastoral sites of this period suggests that the Saharans ranged their herds over widely separated summer and winter grazing grounds.
9. According to paragraph 5， each of the following was true about the early Saharan people EXCEPT：
A. They had few possessions apart from cattle.
B. After about 5，000 B.C.， they lived primarily in caves that were located deep in the desert.
C. Between the summer and winter seasons， they moved their herds over long distances.
D. They painted animals and scenes of daily life on the walls of caves.
前者是否定，而后者为肯定。为什么不选它呢？那同学们不妨观察B选项和原文意思的区别。选项是说沙哈拉人们住在沙漠深处，那原文呢？The Saharan people left a remarkable record of their lives painted on the walls of caves deep in the desert. 这话说的是纪录人们生活的图画是在沙漠深处的墙上。很明显，选项和文章的意思是矛盾的。