xdf蓝皮书,249,254,260,应该没有讨论过

254. samples from a ceramic vase found at a tomb in Sicily prove that the vase was manufactured in Greece. Since the occupant of the tomb died during the reign of a Sicilian ruler who lived 2,700 years ago, the location of the vase indicates that there was trade between Sicily and Greece 2,700 years ago.

Which of the following is an assumption on which the argument depends?

C. At the time that the occupant of the tomb was alive, there were ships capable of transporting large quantities of manufactured goods between Sicily and Greece.

D. The vase that was found at the Sicilian tomb was not placed there many generations later by descendants of the  occupant of the tomb.

正确答案是D, 我没有异议,但觉得C也没错啊?

260. last year the worldwide paper industry used over twice as much fresh pilp(pulp made directly from raw plant fibers) as recycled pulp (pulp made from wastepaper). a paper-industry analyst has projected that by 2010 the industry will use at least as much recycled pulp annually as it does fresh pulp, while using a greater quantity of fresh pulp that it did last year.

if the information above is correct and the analyst's projections prove to be accurate, which of the following projections must also be accurate?

A. In 2010 the paper industry will use at least twice as much recycled pulp as it did last years.

没有头绪呢

249. over the last century, paleontologists have used small differences between fossil speciments to classify triceratops into sixteen species. this classification is unjustified, however, since the speciments used to distinguish eleven of the species come from animals that lived in the same area at the same time

which of the following, if true, would enable the conclusion of the argument to be properly drawn?

C. no geographical area ever supports more than three similar species at the same time.

不太能理解

救.....命.....啊~~~~

*_*