[A] For example, the Moche lords of Sipdn in coastal Peru were buried in about ad 400 in fine cotton dress and with exquisite ornaments of bead, gold, and silver. Few burials rival their lavish sepulchres. Being able to trace the development of such rituals over thousands of years has added to our understanding of the development of human intellect and spirit.
[B] By 40,000 years ago people could be found hunting and gathering food across most of the regions of Africa. Populations in different regions employed various technological developments in adapting to their different environments and climates.
[C] Archaeological studies have also provided much information about the people who first arrived in the Americas over 12,000 years ago.
[D] The first fossil records of vascular plants--that is, land plants with tissue that carries food--appeared in the Silurian period. They were simple plants that had not developed separate stems and leaves.
[E] One site in Tanzania even reveals footprints of humans from 3.6 million years ago. Some sites also contain evidence of the earliest use of simple tools. Archaeologists have also recorded how primitive forms of humans spread out of Africa into Asia about 1.8 million years ago, then into Europe about 900,000 years ago.
[F] One research project involves the study of garbage in present-day cities across the United States. This garbage is the modem equivalent of the remains found in the archaeological record. In the future, archaeologists will continue to move into new realms of study.
[G] Other sites that represent great human achievement are as varied as the cliff dwellings of the ancient Anasazi (a group of early Native Americans of North America) at Mesa Verde, Colorado; the Inca city of Machu Picchu high in the Andes Mountains of Peru; and the mysterious, massive stone portrait heads of remote Easter Island in the Pacific.
Unit 20
Directions
In the following article, some sentences have been removed. For Questions 41--45, choose the most suitable one from the list A--G to fit into each of the numbered blank. There are two extra choices that do not fit in any of the gaps Mark your answers on ANSWER SHEET 1. (10 points)
Rain forest structure is distinct from most other forest types because of its many layers of vegetation, referred to as strata. The lowest stratum is the understory, composed of palms, herbaceous plants (such as wild ginger), and tree seedlings and saplings. (41) . Many have deep red coloring on the underside of their leaves to capture some of the scarce light that does manage to reach the forest understory. This red coloring enables understory plants to absorb light of different wavelengths than do the plants with rich, green-foliaged canopy, the umbrella-shaped upper structure of trees. Above the forest floor but below the canopy are one or more midstory strata, made up of woody plants, such as large shrubs and midsized trees.
The overstory is the canopy, in which the tree crowns form a continuous layer that captures the major part of the rainwater and sunlight hitting the forest. The height of the canopy varies from region to region and forest to forest, ranging from 20 to 50 m (65 to 165 ft). (42) . Researchers use hot air balloons, cables, catwalks, towers, sophisticated tree-climbing gear, and even robots to study the millions of plants and animals that make their home high up in the forest canopy. Canopy researchers also use huge cranes that are dropped into the heart of the forest by helicopters. Suspended from the crane's long, movable arm is a large cabin that functions as a mobile treetop laboratory. Moving from tree to tree, forest researchers collect specimens, conduct experiments, and observe life in the canopy frontier.
The highest stratum of the rain forest is made up of the emergent trees, those individuals that stick up above the forest canopy. Emergents, which do not form a continuous layer, are
usually the giants of the forest, reaching heights of 35 to 70 m (115 to 230 ft) or more, and trunk sizes of over 2 m (6. 6 ft) in diameter. (43) . However, these trees tend to be so large that they collectively account for the vast majority of the woody mass, or biomass, of the forest.
The nicely ordered strata of the rain forest, including the continuous layer of the canopy, are regularly disturbed by naturally occurring events, such as failing trees. Trees in a rain forest canopy are often interconnected by vines, and a falling tree may pull as well as push other trees down with it, producing a domino effect of falling trees. The resulting opening in the forest canopy enables light to pour onto the forest floor. (44)
.
Other natural disturbances create even larger openings in the forest canopies. For example, along the hurricane belt in the Caribbean and the typhoon belt along the western Pacific, some forests are substantially altered when high winds and storms blow down hundreds of trees every few decades. (45) . Scientists have found that these natural disturbances and the subsequent forest regeneration are a vital process that leads to healthy and diverse forests.
[A] New plants and animals then move into the area and begin to grow.
[B] Just 2 percent of the sunlight goes through the many layers of leaves and branches above, so understory plant species have developed special traits to cope with low light levels.
[C] On a smaller scale, large mammals, such as elephants, regularly destroy rain forest vegetation in the Congo River Basin in Africa.
[D] An understory of shorter trees and a lacework of woody vines, or lianas, produce a forest of such complex internal architecture that many animals, including some sizable ones, rarely or never descend to the ground.
[E] Less than one percent of the trees in the forest reside in the canopy and emergent layers.
[F] Because more light penetrates the canopy, however, the vegetation of the understory and forest floor is better developed than in the tropics.
[G] The rich, green canopy is teeming with life, and forest researchers have developed ingenious methods for accessing this mysterious ecosystem.
Key to paper
Unit 1
CCDBA; CACBD, ABDCC,BDACB
Unit 2
DDACB,ADBBA; CDABC; ADACB
Unit 3
CADAB; DCBAB; ACDBA; CDABB
Unit 4
ADACB,BDBAA,BDACB,BACBD
Unit 5
CAADC,CBCAC,DADBD,BBAAB
Unit 6
DBCBA,AACDD,BDCAB,BCC(BA)D
Unit 7
BADBC; ACBAD;CBBCA; BADDA
Unit 8
BAD(AD both right)B; DDD(C no answer)A; CDAAC; CABDD
Unit 9
DAADC, DCABA, ACCBA, DDDBC
Unit 10
DDACB, ACDAC, BDDBC, ACBBB
Unit 11
ACDAB, CDDAB, CDAAA, BADCC
Unit 12
DDBCA, DDDCB, DBDDA, DACCC
Unit 13
DDDCA, A DCBD, ADCDB Text 4(omit)
Unit 14
B，F，E，D，A
Unit 15
C，F，A，E，B
Unit 16
F，A，D，B，C
Unit 17
D，G，A，E，B
Unit 18
F，A，C，G，D
Unit 19
E，C，G，A，F
Unit 20
B, G, E, A, C
