Maps made by non-Native Americans to depict Native American land tenure (land tenure:土地所有制), resources and population distributions appeared almost as early as Europeans’ first encounters with Native Americans and took many form: missionaries’ field sketches, explorers’ drawings, and surveyors’ maps, as well as maps rendered in connection with treaties involving land transfers. Most existing maps of Native American lands are reconstructions that are based largely on archaeology, oral reports, and evidence gathered from observers’ accounts in letter, diaries, and official reports; accordingly, the accuracy of these maps is especially dependent on the mapmakers’ own interpretive abilities.第一段：介绍非土著人画的地图的形式、来源
Many existing maps also reflect the 150-year role of the Bureau of Indian Affairs (BIA) in administering tribal lands. Though these maps incorporate some information gleaned directly from Native Americans, rarely has Native American cartography contributed to this official record, which has been compiled, surveyed, and authenticated by non-Native American. Thus our current cartographic record (cartographic record: 制图资料) relating to Native American tribes and their migrations and cultural features, as well as territoriality and contemporary trust lands, reflects the origins of the data, the mixed purposes for which the maps have been prepared, and changes both in United States government policy and in non-Native Americans’ attitudes toward an understanding of Native Americans.第二段：以描述BIA的地图为例，反映了什么，列举
268. Which of the following best describes the content of the passage?主题题
(A) A chronology of the development of different methods for mapping Native Americans无
(B) A discussion of how the mapmaking techniques of Native Americans differed from those of Europeans无，文中讲述的是非土著人的画图技术
(C) An argument concerning the present-day uses to which historical maps of Native American lands are put无，文中关注的是起源，而不是当今的用法
(D) An argument concerning the nature of information contained in maps of Native American lands（D）
(E) A proposal for improving the accuracy of maps of Native American lands无
答案是D 请问原文是说明文 为何会有An argument ---观点 论证呢
类似地一题
Passage 106 (6/17)19/4，
Researchers compared the number of tooth fractures in present-day carnivores with tooth fractures in carnivores that lived 36,000 to 10,000 years ago and that were preserved in the Rancho La Brea tar pits in Los Angeles. The breakage frequencies in the extinct species were strikingly higher than those in the present-day species.现象：古代的牙齿折断率高于 现代
In considering possible explanations for this finding, the researchers dismissed demographic（adj.人口统计学的） bias because older individuals were not overrepresented in the fossil samples. They rejected preservational bias because a total absence of breakage in two extinct species demonstrated that the fractures were not the result of abrasion within the pits. They ruled out local bias because breakage data obtained from other Pleistocene sites were similar to the La Brea data. The explanation they consider most plausible is behavioral differences between extinct and present-day carnivores—in particular, more contact between the teeth of predators and the bones of prey due to more thorough consumption of carcasses by the extinct species. Such thorough carcass consumption implies to the researchers either that prey availability was low, at least seasonally, or that there was intense competition over kills (something killed) and a high rate of carcass theft due to relatively high predator densities.解释原因：否定三种，肯定一种
231. The primary purpose of the passage is to 主题题
(A) present several explanations for a well-known fact
(B) suggest alternative method of resolving a debate无
(C) argue in favor of a controversial theory无
(D) question the methodology used in a study（E）无
(E) discuss the implications（a suggestion that is not made directly but that people are expected to understand or accept） of a research finding
答案是E 这里的implications是做为原因理解 还是作为含意理解
从原文来说 做原因 可能更合适
感觉在做主题题中一些用词比较模糊 大家是如何解决的
谢谢 | 
