专四专八考试

【单选题】Once found almost entirely in the western United States and inAsia, dinosaur fossils are now being discovered on all seven continents.
A、host of new revelations emerged in 1998 that promise to reshape scientists’ views of dinosaurs, including what they looked like and when and where they liveD、
It is doubtful that Tyrannosaurus Rex had lips or that Triceratops had cheeks, says Lawrence Witmer, an assistant professor of anatomy at Ohio University inAthens, Ohio. He reached its conclusions by using high-tech computerized axial tomographyCT orCAT) scans along with comparative anatomy studies. For example, the theory that Triceratops and similar dinosaur species had cheeks was based on past comparisons with mammals such as sheep.But Witmer’s careful analysis found the structure of the triceratops jaw and skull made it more likely that Triceratops had a beak like that of an eagle. Witmer said that scientists should use birds and crocodiles as models when researching the appearance of dinosaurs.
In early October scientists announced that they had confirmed the discovery of a new type of ceratopsian dinosaur. The dinosaur’s bones, found in New Mexico in 1996, are forcing paleontologists to rethink their theories about when ceratopsians migrated to what is now NorthAmeric
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Scientists previously thought that ceratopsians, the group that included the well-known Triceratops. arrived in NorthAmerica fromAsia between 70 million and 80 million years ago.During this time, the lateCretaceous PerioD、the earth’s two supercontinents—Laurasia in the north and Gondwanaland in the south—were in the process of pulling apart, cutting dinosaur populations off from each other and interrupting migratory patterns.
The fossilized bones, found by paleontologistDoug Wolfe of the Mesa Southwest Museum inArizona, date to about 90 million yeses ago. This could mean that ceratopsians originated in NorthAmerica and migrated toAsia rather than the reverse, paleontologists saiD、
An expedition from the Universities ofAlaska inAnchorage and Fairbanks has discovered a region in remote northernAlaska so rich in fossilized dinosaur tracks that team members dubbed it the "dino expressway". The trampled area was found during the summer of 1998 onAlaska’s North Slope near theBrooks Range.
The team found 13 new track sites and made casts from the prints of five different types of dinosaurs. The rock in which the prints were found dates to more than 100 million years ago, or about 25 million years older than the previously discovered signs of dinosaurs in theArctic region. Paleontologists said that the new findings provide important evidence that dinosaurs migrated betweenAsia and NorthAmerica during the early and mid-Cretaceous PerioD、beforeAsia split off into its own continent.
Two rich fossil sites in the hills ofBolivia have been recently discovered, exciting paleontologists and dinosaur buffs. This discovery includes one of the most spectacular dinosaur trackways ever founD、
The discovery of a large site in the mountain region of Kila Kila in southernBolivia was announced in early October. Here scientists found the tracks of at least two unknown species of dinosaur. These included a large quadruped (four. footed) dinosaur that was probably about 20 m (about 70 ft) long.
The other site, located not far from theBolivian city of Sucre, was uncovered in a cement quarry by workers several years ago but was not brought to paleontologists’ attention until the middle of 1998. The site features a vertical wall covered with thousands of dinosaur prints representing more than 100 different species. The tracks date back to between 65 million and 70 million years ago. Since dinosaurs are believed to have died out around 65 million years ago, the prints were likely made by some of the last dinosaurs on earth. Paleontologists hope to study the site and learn about the diet and physical charac
网考网参考答案：D
网考网解析：
根据关键词“a new type of ceratopsian dinosaur”首先找到第三段，其最后一句提到：“新发现将改变关于何时这种龙迁入美洲的理论”，继续看下去，终于找到关键句：第五段的第二句“This could mean that ceratopsians originated in North America and migrated to Asia rather than the reverse”(这可能意味着ceratopsians发源于北美洲而后迁徙到亚洲，而不是相反)，故D为正确答案。 document.getElementById("warp").style.display="none"; document.getElementById("content").style.display="block"; 查看试题解析出处>>