Directions:

　　Read each passage carully and then answer the questions about it. For each question, decide on the basis of the passage which one of the choices best answers the questions.

　　Radiation from the Sun continuously breaks two-atom oxygen molecules into single atoms. Some of these link up with ordinary oxygen molecules and form ozone. Some rejoin other free singles and revert to stable molecules. This Sun-energy process, if lt undisturbed, maintains a fairly constant supply of ozone above the Earth’s surface. The ozone layer begins about eight miles up and is distributed thinly to about thirty miles up. This lofty umbrella of ozone shields the Earth from much of the Sun’s deadly ultraviolet rays. Without the ozone cover, life on Earth would be literally sunburned to death.

　　Some scientists believe that relatively small amount of synthetic chemicals, such as spray-can fluorocarbon or jet exhaust, reach the upper limits of the atmosphere and break down the three-atom ozone molecules. It is also believed that just one atom of the spray-can or get pollutant can affect vast numbers of ozone molecules. Weather research satellites have observed the ozone shield in great detail, but their data have neither put to rest the “doomsday theories” nor incited a global campaign to stop destroying the Earth’s protective covering.

　　1. According to the passage, ozone is a

　　(A) kind of radiation

　　(B) deadly ultraviolet ray

　　(C) combination of oxygen atoms

　　(D) synthetic chemical

　　(E) free-floating atom

　　2. The destruction of the ozone layer would most likely result in a decrease in

　　(A) life on Earth

　　(B) air pollution

　　(C) spray-can gases

　　(D) severe cases of sunburn

　　(E) radiation from the Sun

　　In the sixteenth century, an age of great marine and terrestrial exploration, Ferdinand Magellan led the first expedition to sail around the world. As a young Portuguese noble, he served the king of Portugal, but he became involved in the quagmire of political intrigue at court and lost the king&aposs favor. After he was dismissed from service to the king of Portugal, he offered to serve the future Emperor Charles V of Spain.

　　A papal decree of 1493 had assigned all land in the New World west of 50 degrees W longitude to Spain and all the land east of that line to Portugal. Magellan offered to prove that the East Indies fell under Spanish authority. On September 20, 1519, Magellan set sail from Spain with five ships. More than a year later, one of these ships was exploring the topography of South America in search of a water route across the continent. This ship sank, but the remaining four ships searched along the southern peninsula of South America. Finally they found the passage they sought near a latitude of 50 degrees S. Magellan named this passage the Strait of All Saints, but today we know it as the Strait of Magellan.

　　One ship deserted while in this passage and returned to Spain, so fewer sailors were privileged to gaze at that first panorama of the Pacific Ocean. Those who remained crossed the meridian we now call the International Date Line in the early spring of 1521 after ninety-eight days on the Pacific Ocean. During those long days at sea, many of Magellan&aposs men died of starvation and disease.

　　Later Magellan became involved in an insular conflict in the Philippines and was killed in a tribal battle. Only one ship and seventeen sailors under the command of the Basque navigator Elcano survived to complete the westward journey to Spain and thus prove once and for all that the world is round, with no precipice at the edge.

　　1.The sixteenth century was an age of great ___exploration.

　　A. cosmic

　　B. land

　　C. mental

　　D. common man

　　E. none of the above

　　2. Magellan lost the favor of the king of Portugal when he became involved in a political ___.

　　A. entanglement

　　B. discussion

　　C. negotiation

　　D. problems

　　E. none of the above

　　3. The Pope divided New World lands between Spain and Portugal according to their location on one side or the other of an imaginary geographical line 50 degrees west of Greenwich that extends in a ___ direction.

　　A. north and south

　　B. crosswise

　　C. easterly

　　D. south east

　　E. north and west

　　4. One of Magellan&aposs ships explored the ___ of South America for a passage across the continent.

　　A. coastline

　　B. mountain range

　　C. physical features

　　D. islands

　　E. none of the above

　　5. Four of the ships sought a passage along a southern ___.

　　A. coast

　　B. inland

　　C. body of land with water on three sides

　　D. border

　　E. answer not available

　　6. The passage was found near 50 degrees S of ___.

　　A. Greenwich

　　B. The equator

　　C. Spain

　　D. Portugal

　　E. Madrid

　　7. In the spring of 1521, the ships crossed the ___ now called the International Date Line.

　　A. imaginary circle passing through the poles

　　B. Imaginary line parallel to the equator

　　C. area

　　D. land mass

　　E. answer not found in article

　　答案：

　　1. B 2. A 3. A 4. C 5.C,6 B 7A

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