【正文】 en, Germany, present an interesting case for analysis. The ichthyosaur remains are found in black, bituminous marine shales deposited about 190 million years ago. Over the years, thousands of specimens of marine reptiles, fish, and invertebrates have been recovered from these rocks. The quality of preservation is outstanding, but what is even more impressive is the number of ichthyosaur fossils containing preserved embryos. Ichthyosaurs with embryos have been reported from 6 different levels of the shale in a small area around Holzmaden, suggesting that a specific site was used by large numbers of ichthyosaurs repeatedly over time. The embryos are quite advanced in their physical development。 their paddles, for example, are already well formed. One specimen is even preserved in the birth canal. In addition, the shale contains the remains of many newborns that are between 20 and 30 inches long. Why are there so many pregnant females and young at Holzmaden when they are so rare elsewhere? The quality of preservation is almost unmatched, and quarry operations factors do not account for the interesting question of how there came to be such a concentration of pregnant ichthyosaurs in a particular place very close to their time of giving birth. Questions 3441 The Lewis and Clark expedition, sponsored by President Jefferson, was the most important official examination of the high plains and the Northwest before the War of 1812. The President39。s secretary, Captain Meriwether Lewis, had been instructed to explore the Missouri River, and such principal streams of it as, by its course and munication with the waters of the Pacific Ocean …may offer her most direct and practicable water munication across the continent, for the purposes of merce. Captain William Clark, the younger brother of famed Gee Rogers Clerk, was invited to share the mand of the exploring party. Amid rumors that there were prehistoric mammoths wandering around the unknown region and that somewhere in its wilds was a mountain of rock salt 80 by 45 miles in extent, the two captains set out. The date was May 14, 1804. Their point of departure was the mouth of the Wood River, just across the Mississippi from the entrance of the Missouri River. After toiling up the Missouri all summer, the group wintered near the Mandan villages in the center of what is now North Dakota. Resuming their journey in the spring of 1805, the men worked their way along the Missouri to its source and then crossed the mountains of western Montana and Idaho. Picking up a tributary of the Columbia River, they continued westward until they reached the Pacific Ocean, where they stayed until the following spring. Lewis and Clark brought back much new information, including the knowledge that the continent was wider than originally supposed. More specifically, they learned a good deal about river drainages and mountain TOEFL9505閱讀真題 7 barriers. They ended speculation that an easy coasttocoast route existed via the MissouriColumbia River systems, and their reports of the climate, the animals and birds, the trees and plants, and the Indians of the West – though not immediately published – were made available to scientists. Questions 4250 For a century and a half the piano has been one of the most popular solo instruments for Western music. Unlike string and wind instrument, the piano is pletely selfsufficient, as it is able to play both the melody and its acpanying harmony at the same time. For this reason, it became the favorite household instrument of the nieenth century. The ancestry of the piano can be traced to the early keyboard instruments of the fifteenth and sixteenth centuries – the spi, the dulcimer, and the virginal. In the seventeenth century the an, the clavichord, and the harpsichord became the chief instruments of the keyboard group, a supremacy they maintained until the piano supplanted them at the end of the eighteenth century. The clavichord39。s tone was metallic and never powerful。 nevertheless, because of the variety of tone possible to it, many posers found the clavichord a sympathetic instrument for concert use, but the character of the tone could not be varied save by mechanical or structural devices. The piano was perfected in the early eighteenth century by a harpsichord maker in Italy (though musicologists point out several previous instances of the instrument). This instrument was called a piano e forte(soft and loud), to indicate its dynamic versatility。 its strings were struck by a recoiling hammer with a feltpadded head. The wires were much heavier in the earlier instruments. A series of mechanical improvements continuing well into the nieenth century, including the introduction of pedals to sustain tone or to soften it, the perfection of a metal frame and steel wire of the finest quality, finally produced an instrument capable of myriad tonal effects from the most delicate harmonies to an almost orchestral fullness of sound, from a liquid, singing tone to a sharp, percussive brilliance. Questions 110 The House of Native American Tribe Keywords: United States, pueblos, buildings, chambers, niches Another early Native American tribe in what is now the southwestern part of the United States was the Anasazi. By A. D. 800 the Anasazi Indians were constructing multistory pueblosmassive, stone apartment pounds. Each one was virtually a stone town, which is why the Spanish would later call them pueblos, the Spanish word for towns. These pueblos represent one of the Anasazis39。 supreme achievements. At least a dozen large stone houses took shape below the bluffs of Chiaco Canyon in northwest New Mexico. They were built with masonry walls more than a meter thick and adjoining apartments to acmodate dozens, even hundreds, of fam