Among the alder's valuable ecological contributions is its capacity to fix nitrogen in nitrogen-deficient soils. Alder roots contain clusters of nitrogen-fixing nodules like those found on legumes such as beans. in addition, newly developing soils exposed by recent glacier retreat and planted with alders show that these trees are applying the equivalent of ten bags of high-nitrogen fertilizer to each hectare per year. Other chemical changes to soil i
( A& |& @7 r: r' a; k! \$ dn which they are growing Include a lowering of the base content and rise In soil acidity, as well as a substantial addition of carbon and calcium. to the soil,5 l6 X2 S' A0 D
! O. i$ M) u* x+ E! ?/ Q& f( ^% z3 Q. u Another important role many alders play in the wild, particularly in 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.
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31. What does the passage mainly discuss?
7 u# K3 H7 ?8 O/ ]/ z& N! _6 e(A)Differences between alder trees and Douglas fir trees1 l+ a: U3 ]7 k% G7 b1 r
(B)Alder trees as a source of timber( d6 R4 x% f" C9 x
(C)Management plans for using alder trees to improve soil2 D: ?- o$ [6 `( v7 ] ~
(D)The relation of alder trees to their forest environments
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32. The word "dense" in line I is closest in meaning to
0 H8 B" m8 h/ f(A) dark
$ E- ~- j7 N0 |" e. x9 w(B) tall
' |+ P. H) M6 h8 p$ ~(C) thick
. h- H/ T6 `3 P6 K9 [(D) broad7 g1 ?# z' p: {6 ]: y
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33. Alder trees can suppress the growth of nearby trees by depriving them of
( x. M- e# p& }& U$ L; W$ E j(A) nitrogen
y) ? Q% e8 f(B) sunlight/ B+ B( O5 y. E" m9 g2 n
(C) soil nutrients0 M1 `+ ?5 ]; P& d
(D) water
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34. Thc passage suggests that Douglas fir trees are ( ^- ]0 M! d. U7 Z7 @* u
(A)a type of alder# w8 L" ^) p# t' O
(B)a type of evergreen0 ?& V' C- U# N$ z
(C)similar to sword ferns
9 [; l& G6 U, t! N: r6 g3 `3 k h(D)fast-growing trees; X# b. q, ~- r- W5 x$ L
9 J9 D# Y" p) f- C35. It can be inferred from paragraph I that hemlock trees
7 p9 q7 u4 y1 M, e1 N' x(A) are similar in size to alder trees.4 K3 a+ T/ Z6 {0 U3 U
(B) interfere with the growth of Douglas fir trees
2 O- i* N: S6 ^( E4 l5 s(C) reduce the number of alder trees In the forest
' R* ~+ ^( I. f- {& i8 r( G(D) need less sunlight than do Douglas fir trees8 }. Y5 c G! h
/ T1 h2 p7 x2 P' a; F: \- L36. It can be inferred from paragraph 2 that previous generations of foresters
* P: o2 g" h) Y* c8 z7 H( w. g(A) did not study the effects of alders on forests0 [; ?% Y9 I/ u& `+ u( F: E, Q
(B) did not want alders In forests% c7 F- T, ]- T( W6 N8 `
(C) harvested alders for lumber
: W5 x4 }, z! `8 ~8 v(D) used alders to control the growth of evergreens& T/ H# D! A1 R1 C( x) E
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37. The word "they" in line 21 refers to # g$ f8 o8 ]+ C" ?8 {* S
(A) newly developing soils" F/ f. Y$ {+ W" ^0 q
(B) alders
4 f' C4 w6 [2 l& K1 c2 V* H3 b(C) bags3 k( k; }# p( Y# e0 B* k, D
(D) chemical changes4 r7 A6 n, ^0 B+ i7 U
- Z2 B, z) ~3 S# m38. According to the passage that alders are used in mountainous areas to 4 m+ Y! G8 I( Y
(A) nitrogen
. e5 s5 f' w9 S6 L, w(B) calcium
% E0 u7 `' J. I(C) carbon
( [+ e7 j: O( I5 \) u$ T% I5 e(D) oxygen. J# s; z7 L" m
& v& B" r T& ]' {- W39. It can be Inferred from the passage that alders are used in mountainous areas to & t/ A& f2 F# d5 F4 x1 |& b
(A) prevent water from carrying away soil
$ ` Q" @1 i& `4 K ^$ r(B) hold the snow% x3 S: O2 \# x; @
(C) protect mines
) u) x: e$ q$ h) D# _0 C- ?(D) provide material for housing
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40. What is the author's main purpose in the passage?
% U" l! @' v9 ? k/ t; V. ^! Y8 u(A) To argue that alder trees are useful in forest management
" k4 ~$ m7 z! R* \7 o) |2 W5 A+ z(B) To explain the life cycle of alder trees
* ]- b% m! _& Y2 [4 E(C) To criticize the way alders take over and eliminate forests- Y6 a8 Q! n$ n+ q: }/ W7 _; E
(D) To illustrate how alder trees control soil erosion
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6 y% Y: P( h, @8 [4 d& J- FQuestions 41-50
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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.0 f' e; U& z9 Y, o, x6 c
3 O- p1 `4 d) X: K4 P 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 countryside farmers therefore relieved the burden of the daily routine with such relaxation as hunting. fishing, and trapping. When a neighbor needed help, families rallied from miles around to assist In building a house or barn, husking corn, shearing sheep. or chopping wood. Food, drink, and celebration after the group work provided relaxation and soothed weary muscles.
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The most eagerly anticipated social events were the rural fairs, Hundreds of men, women, and children attended from far and near. The men bought or traded farm animals and acquired needed merchandise while the women displayed food prepared in their kitchens, and everyone, Including the youngsters, watched or participated in a variety of competitive sports, with prizes awarded to the winners. These events typically included horse races, wrestling matches, and foot races, as well as some nonathletic events such as whistling competitions. No other occasions did so much to relieve the isolation of farm existence. |