Choose the best answer to complete the passage.
Since the earliest times, trees have always been very useful and important to
man 36 made use of them in many ways. Even today trees
continue to serve man 37 many ways.
Trees
provide man with fruits and buildings in the form of wood. 38 trees
it would be impossible to build house, boats and even bridges. Furniture(家具) such as tables. chairs and beds 39
wood.
In the
tropics(热带地区) where it is very
hot all though the year, trees 40 man from the terrible
heat. They are also used in preventing good and rich top soil from 41 during
heavy rains which are so 42 in the tropics.
43 there were no trees or vegetation of some kinds to hold back
the soil with their roots heavy rains would wash the rich surface soil away. 44
is so important and necessary to agriculture(农业). The result is that the land becomes a
desert.
There are 45
many desert areas in world. A long time ago those desert areas must
have been very rich fertile(肥沃的)
areas, but since our ancestors(祖先)
in the 46 hadn’t 47 knowledge about
science of nature, they cut down all the trees in the areas where they lived
and never planted new 48 . By and by, the rich surfaces
soil 49 away and washed away by strong winds and heavy rains.
In the end the land was turned into 50 deserts where nothing
could grow.
(
) 36. A. which
B. who
C. he
(
) 37. A. at
B.
for
C. in
(
) 38. A. Have
B. With
C. Without
(
) 39. A. are made of B. is made
of C. is made from
(
) 40. A.
protect
B. help
C. make
(
) 41. A. be washing away
B. washing away C. being washed away
(
) 42. A. common
B. commonly C. usually
(
) 43. A.
But
B.
And
C. If
(
) 44. A. that
B.
what
C. where
(
) 45. A. such
B.
so
C. very
(
) 46. A. pass
B.
past
C. passed
(
) 47. A.
any
B. some
C. enough
( ) 48. A.
ones
B.
one
C. some
(
) 49. A. was blew B. was
blown C. blows
(
) 50. A. use
B. useful
C. useless