光说无凭，我们以TPO51的“Memphis: United Egypt’s First Capital”为例子，看看两种类型的错误选项分别错在何处。
Equally important for the national administration was the ability to control communications within Egypt. The Nile provided the easiest and quickest artery of communication and the national capital was, again, ideally located in this respect. Recent geological surveys of the Memphis region have revealed much about its topography in ancient times. It appears that the location of Memphis may have been even more advantageous for controlling trade, transport, and communications than was previously appreciated. Surveys and drill cores have shown that the level of the Nile floodplain has steadily risen over the last five millenniums. When the floodplain was much lower, as it would have been in predynastic and early dynastic times, the outwash fans (fan-shaped deposits of sediments) of various wadis (stream-beds or channels that carry water only during rainy periods) would have been much more prominent features on the east bank. The fan associated with the Wadi Hof extended a significant way into the Nile floodplain, forming a constriction in the vicinity of Memphis. The valley may have narrowed at this point to a mere three kilometers, making it the ideal place for controlling river traffic.
Furthermore, the Memphis region seems to have been favorably located for the control not only of river-based trade but also of desert trade routes. The two outwash fans in the area gave access to the extensive wadi systems of the eastern desert. In predynastic times, the Wadi Digla may have served as a trade route between the Memphis region and the Near East, to judge from the unusual concentration of foreign artifacts found in the predynastic settlement of Maadi. Access to, and control of, trade routes between Egypt and the Near East seems to have been a preoccupation of Egypt’s rulers during the period of state formation. The desire to monopolize foreign trade may have been one of the primary factors behind the political unification of Egypt. The foundation of the national capital at the junction of an important trade route with the Nile valley is not likely to have been accidental. Moreover, the Wadis Hof and Digla provided the Memphis region with accessible desert pasturage. As was the case with the cities of Hierakonpolis and Elkab, the combination within the same area of both desert pasturage and alluvial arable land (land suitable for growing crops) was a particularly attractive one for early settlement; this combination no doubt contributed to the prosperity of the Memphis region from early predynastic times.
C.The rulers of unified Egypt enjoyed a monopoly over foreign trade because all such trade was required to go through the Wadi Digla, to which the rulers controlled all access.
“rulers”，“monopoly”，“trade through he Wadi Digla”，看起来似乎没什么大问题，以上都是在第二段中提到过，甚至重点强调过(如rulers)的词汇。
然而，不知大家是否注意到了这个选项的“特别”之处：在做托福阅读的时候，大家一旦碰见类似“the Wadi Digla”这样专业性极强的专属名词应该立即引起警惕，但不是像绝大多数同学那样对这类名词产生恐惧，而是应该兴奋。为什么呢?因为这类名词通常都是对尤其是阅读最后一题选项正误很好的提示，更是对应原文时非常显著的标志物。
很容易就可以找到，第二段提到了“the Wadi Digla”的主要是这样两处：
“In predynastic times, the Wadi Digla may have served as a trade route between the Memphis region and the Near East…”和“Moreover, the Wadis Hof and Digla provided the Memphis region with accessible desert pasturage.”
同时我们应该注意到在第二次提到“the Wadi Digla”之后，作者紧跟着介绍了两个类似的城市 “the cities of Hierakonpolis and Elkab”：
“As was the case with the cities of Hierakonpolis and Elkab, the combination within the same area of both desert pasturage and alluvial arable land…”
再次回看我们提炼出的两句话，还可以发现别的问题。选项中提到的“all such trade was required to go through the Wadi Digla”其实是对第一句话后续提到的信息的总结，然而，这句话另一个重要的信息在开头：“In predynastic times”，即这句话之后紧跟的所有信息都发生在埃及统一之前，和选项要求的“The rulers of unified Egypt”相冲突。文科类文章中常见以时间逻辑叙述的段落，甚至文章本身。因此，选项中任何对时间段的提示都是极其重要的信息，时间和事件的错位同样也是一个常见错误原因。