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mountainous areas, is to check the rush of water during spring melt. In Japan and elsewhere, the trees are planted to stabilize soil on steep mountain slopes. Similarly, alders have been planted to stabilize and rehabilitate waste material left over from old mines, flood deposits, and landslide areas in both Europe and Asia.

31.What does the passage mainly discuss?
(A)Differences between alder trees and Douglas fir trees
(B)Alder trees as a source of timber
(C)Management plans for using alder trees to improve soil
(D)The relation of alder trees to their forest environments

32.The word "dense" in line I is closest in meaning to
(A) dark
(B) tall
(C) thick
(D) broad

33.Alder trees can suppress the growth of nearby trees by depriving them of
(A) nitrogen
(B) sunlight
(C) soil nutrients
(D) water

34.Thc passage suggests that Douglas fir trees are
(A)a type of alder
(B)a type of evergreen
(C)similar to sword ferns
(D)fast-growing trees

35.It can be inferred from paragraph I that hemlock trees
(A) are similar in size to alder trees.
(B) interfere with the growth of Douglas fir trees
(C) reduce the number of alder trees In the forest
(D) need less sunlight than do Douglas fir trees

36.It can be inferred from paragraph 2 that previous generations of foresters
(A) did not study the effects of alders on forests
(B) did not want alders In forests
(C) harvested alders for lumber
(D) used alders to control the growth of evergreens

37.The word "they" in line 27 refers to
(A) newly developing soils
(B) alders
(C) bags
(D) chemical changes

38.According to the passage that alders are used in mountainous areas to
(A) nitrogen
(B) calcium
(C) carbon
(D) oxygen

39.It can be Inferred from the passage that alders are used in mountainous areas to
(A) prevent water from carrying away soil
(B) hold the snow
(C) protect mines
(D) provide material for housing

40.What is the author s main purpose in the passage?
(A) To argue that alder trees are useful in forest management
(B) To explain the life cycle of alder trees
(C) To criticize the way alders take over and eliminate forests
(D) To illustrate how alder trees control soil erosion

Questions 41-50
      In taking ups new life across the Atlantic, the early European settlers of the United States did not abandon the diversions with which their ancestors had traditionally relieved the tedium of life. Neither the harshness of existence on the new continent nor Line the scattered population nor the disapproval of the clergy discouraged the majority from the pursuit of pleasure. 
     City and country dwellers. of course. conducted this pursuit in different ways. Farm dwellers in their isolation not only found it harder to locate companions in play but also thanks to the unending demands and pressures of their work, felt it necessary to combine fun with purpose. No other set of colonists too so seriously one expression of the period. "Leisure Is time for doing something useful." in the country-side farmers therefore relieved the burden of the daily routine with such double-purpose relaxation as hunting. fishing, and trapping. When a neighbor needed help, families rallied from miles around to assist In buildi本论文由英语论文网提供整理，提供论文代写，英语论文代写，代写论文，代写英语论文，代写留学生论文，代写英文论文，留学生论文代写相关核心关键词搜索。