掌握了gre阅读里的长难句，到了实战演习的时候了。gre阅读练习每日一篇帮助gre考生循序渐进地进行练习和总结。希望gre考生在进行gre阅读练习时，也按着考试时候的时间规定自己的练习，这样才能有效果。

　　Diamonds, an occasional component of rare igneous rocks called lamproites and kimberlites, have never been dated satisfactorily. However, some diamonds contain minute inclusions of silicate minerals, commonly olivine, pyroxene, and garnet. These minerals can be dated by radioactive decay techniques because of the very small quantities of radioactive trace elements they, in turn, contain. Usually, it is possible to conclude that the inclusions are older than their diamond hosts, but with little indication of the time interval involved. Sometimes, however, the crystal form of the silicate inclusions is observed to resemble more closely the internal structure of diamond than that of other silicate minerals. It is not known how rare this resemblance is, or whether it is most often seen in inclusions of silicates such as garnet, whose crystallography is generally somewhat similar to that of diamond; but when present, the resemblance is regarded as compelling evidence that the diamonds and inclusions are truly cogenetic.

　　17. The author implies that silicate inclusions were most often formed

　　(A) with small diamonds inside of them

　　(B) with trace elements derived from their host minerals

　　(C) by the radioactive decay of rare igneous rocks

　　(D) at an earlier period than were their host minerals

　　(E) from the crystallization of rare igneous material

　　18. According to the passage, the age of silicate minerals included in diamonds can be determined due to a feature of the

　　(A) trace elements in the diamond hosts

　　(B) trace elements in the rock surrounding the diamonds

　　(C) trace elements in the silicate minerals

　　(D) silicate minerals’ crystal structure

　　(E) host diamonds’ crystal structure

　　19. The author states that which of the following generally has a crystal structure similar to that of diamond?

　　(A) Lamproite

　　(B) Kimberlite

　　(C) Olivine

　　(D) Pyroxene

　　(E) Garnet

　　20. The main purpose of the passage is to

　　(A) explain why it has not been possible to determine the age of diamonds

　　(B) explain how it might be possible to date some diamonds

　　(C) compare two alternative approaches to determining the age of diamonds

　　(D) compare a method of dating diamonds with a method used to date certain silicate minerals

　　(E) compare the age of diamonds with that of certain silicate minerals contained within them

　　Discussion of the assimilation of Puerto Ricans in the United States has focused on two factors: social standing (social standing: 社会地位) and the loss of national culture. In general, excessive stress is placed on one factor or the other, depending on whether the commentator is North American or Puerto Rican. Many North American social scientists, such as Oscar Handlin, Joseph Fitzpatrick, and Oscar Lewis, consider Puerto Ricans as the most recent in a long line of ethnic entrants to occupy the lowest rung on the social ladder. Such a “sociodemographic” approach tends to regard assimilation as a benign process, taking for granted increased economic advantage and inevitable cultural integration, in a supposedly egalitarian context. However, this approach fails to take into account the colonial nature of the Puerto Rican case, with this group, unlike their European predecessors, coming from a nation politically subordinated to the United States. Even the “radical” critiques of this mainstream research model, such as the critique developed in Divided Society, attach the issue of ethnic assimilation too mechanically to factors of economic and social mobility and are thus unable to illuminate the cultural subordination of Puerto Ricans as a colonial minority.

　　In contrast, the “colonialist” approach of island-based writers such as Eduardo Seda-Bonilla, Manuel Maldonado-Denis, and Luis Nieves-Falcon tends to view assimilation as the forced loss of national culture in an unequal contest with imposed foreign values. There is, of course, a strong tradition of cultural accommodation among other Puerto Rican thinkers. The writings of Eugenio Fernandez Mendez clearly exemplify this tradition, and many supporters of Puerto Rico’s commonwealth status share the same universalizing orientation. But the Puerto Rican intellectuals who have written most about the assimilation process in the United States all advance cultural nationalist views, advocating the preservation of minority cultural distinctions and rejecting what they see as the subjugation of colonial nationalities.

　　This cultural and political emphasis is appropriate, but the colonialist thinkers misdirect it, overlooking the class relations at work in both Puerto Rican and North American history. They pose the clash of national cultures as an absolute polarity, with each culture understood as static and undifferentiated. Yet both the Puerto Rican and North American traditions have been subject to constant challenge from cultural forces within their own societies, forces that may move toward each other in ways that cannot be written off as mere “assimilation.” Consider, for example, the indigenous and Afro-Caribbean traditions in Puerto Rican culture and how they influence and are influenced by other Caribbean cultures and Black cultures in the United States. The elements of coercion and inequality, so central to cultural contact according to the colonialist framework play no role in this kind of convergence of racially and ethnically different elements of the same social class.

　　21. The author’s main purpose is to

　　(A) criticize the emphasis on social standing in discussions of the assimilation of Puerto Ricans in the United States

　　(B) support the thesis that assimilation has not been a benign process for Puerto Ricans

　　(C) dend a view of the assimilation of Puerto Ricans that emphasizes the preservation of national culture

　　(D) indicate diciencies in two schools of thought on the assimilation of Puerto Ricans in the United States

　　(E) reject the attempt to formulate a general framework for discussion of the assimilation of Puerto Ricans in the United States

　　22. According to the passage, cultural accommodation is promoted by

　　(A) Eduardo Seda-Bonilla

　　(B) Manuel Maldonado-Denis

　　(C) the author of Divided Society

　　(D) the majority of social scientists writing on immigration

　　(E) many supporters of Puerto Rico’s commonwealth status

　　23. It can be inferred from the passage that a writer such as Eugenio Fernandez Mendez would most likely agree with which of the following statements concerning members of minority ethnic groups?

　　(A) It is necessary for the members of such groups to adapt to the culture of the majority.

　　(B) The members of such groups generally encounter a culture that is static and undifferentiated.

　　(C) Social mobility is the most important feature of the experience of members of such groups.

　　(D) Social scientists should emphasize the cultural and political aspects of the experience of members of such groups.

　　(E) The assimilation of members of such groups requires the forced abandonment of their authentic national roots.

　　24. The author implies that the Puerto Rican writers who have written most about assimilation do NOT do which of the following?

　　(A) Regard assimilation as benign.

　　(B) Resist cultural integration.

　　(C) Describe in detail the process of assimilation.

　　(D) Take into account the colonial nature of the Puerto Rican case.

　　(E) Criticize supporters of Puerto Rico’s commonwealth status.

　　25. It can be inferred from the passage that the “colonialist” approach is so called because its practitioners

　　(A) support Puerto Rico’s commonwealth status

　　(B) have a strong tradition of cultural accommodation

　　(C) emphasize the class relations at work in both Puerto Rican and North American history

　　(D) pose the clash of national cultures as an absolute polarity in which each culture is understood as static and undifferentiated

　　(E) regard the political relation of Puerto Rico to the United States as a significant factor in the experience of Puerto Ricans

　　26. The author regards the emphasis by island-based writers on the cultural and political dimensions of assimilation as

　　(A) ironic

　　(B) dangerous

　　(C) fitting but misdirected

　　(D) illuminating but easily misunderstood

　　(E) peculiar but benign

　　27. The example discussed in lines 51-54 is intended by the author to illustrate a

　　(A) strength of the sociodemographic approach

　　(B) strength of the “colonialist” approach

　　(C) weakness of the sociodemographic approach

　　(D) weakness of the “colonialist” approach

　　(E) weakness of the cultural-accommodationist approach

答案：17-27：DCEBDEAAECD

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