41 According to the passage, a greenhouse is built to </p> A keep the plants warm. + z* z6 b3 w) ?) Q
B prevent air pollution.
' D7 R& A0 L- @4 N8 S$ s C stop the greenhouse effect. 9 E1 C' c5 ^. j0 X1 H
D produce useful gases. . {: b" p: n: a/ s# j% |9 J7 K! z8 g, o
42 Without the greenhouse gases, the earth would www.examw.com
: c" b* `4 t0 M1 l5 _3 i A become warmer.
2 U& F1 {3 U! Q; k3 g, C+ A" C B be much colder. ; x- {, S9 O) }9 @, E
C move more slowly. & {# ^) J4 N0 b, |
D move quickly. ; d3 Y. D- w$ X$ `$ u9 z
43 A major cause of the increase in the greenhouse gases is
6 c0 z l* y: [" K A the burning of trees and crops.
% F: |4 U3 d* [# ]9 f B the building of many greenhouses. ; }5 E) h$ W0 E0 j
C the burning of large quantities Of coal and oil.
$ N! b7 _5 [; ]) O D the flooding of large areas of the world. ' M! Q0 I. x! I/ O( V
44 According to the passage, chlorofluorocarbon gases differ from carbon dioxide in that
8 d$ l8 F' E6 a+ b1 U% j8 ~. c A they are more useful.
6 U$ f. M/ x4 \: t B they are much heavier. & L" n6 {9 w" T8 ~2 n
C they are more efficient in making the' world colder. r& \& Q a) o5 d9 f
D they are more effective in catching the heat from the sun.
* b! X% p c: V2 q 45 A small increase in the earth's temperature may bring about , F( ]- x1 |% |; }# i5 G+ K$ B2 C g9 b
A a decline in agriculture.
" `! K- q/ i3 T. M- A8 `; u B a drop of the sea level. www.ExamW.CoM" l- s" K6 v a, B
C the death of all animals. , v) H/ W8 O/ s* U3 g
D a delay in the greenhouse effect.
' T# Y8 U' Y; W, w$ j5 [ 【参考答案】
; y9 A" M' G5 ]* b' g, h" k6 J+ b 41. A 42. B 43. C 44. D 45. A |