三、概括大意与完成句子 1.
) N: y) c `& e& I Keeping Cut Flowers
. O! W3 F! P N, F8 O While everybody enjoys fresh cut flowers around his house, few people know how to keep them for as long as possible. This may be done by keeping in mind a few simple facts.5 X$ B. x6 y6 [% a
An important thing to remember about cut flowers is that they are sensitive to temperature. For example, studies have shown that cut carnations(康乃馨) retain their freshness eight times longer when kept at 12oC than when kept at 260c. Keeping freshly harvested flowers at the right temperatures is probably the most important aspect of flower care.
6 E) G3 A3 Y$ I( K: l& m Flowers are not intended by nature to live very long. Their biological purpose is simply to attract birds or insects, such as bees, for pollination (授粉). After that, they quickly dry up and die. The process by which flowers consume oxygen and produce carbon dioxide (二氧化碳), called respiration (呼吸), generates the energy the flower needs to give the flower its shape and colour. The making of seeds also depends on this energy. While all living things respire, flowers have a high level of respiration. A result of all this respiration is heat, and for flowers the level of heat relative to the mass of the flower is very high. Respiration also brings about the eventual death of the flower. Thus the greater the level of respiration, the sooner the flower dies.' J6 k! V( G/ x; b% }) K6 H8 E
How, then, to control the rate at which flowers die? By controlling respiration. How is respiration controlled? By controlling temperature. We know that respiration produces heat, but the reverse is also true. Thus by maintaining low temperatures, respiration is reduced and the cut flower will age more slowly.
* j. L# J1 j0 X& G Another vital factor in keeping cut flowers is the quality of the water in which they are placed. Flowers find it difficult to “drink” water that is dirty or otherwise polluted. Even when water looks and smells clean, it almost certainly contains harmful substances that can endanger the flowers. To rid the water of these unwanted substances, household chlorine bleach (含氯漂白剂) can be used in small quantities. It is recommended that 15 drops of chlorine bleach(at 4% solution) be added to each litre of water. The water and solution should also be replaced each day.
$ \2 M% R* c! u' B A. Control of Respiration7 k, e5 _& V O$ n* p( O( h& @) A
B. Beauty of Fresh Cut Flowers% g+ s, o. l! I; n8 G' x% i
C. Role of Respiration2 {! d; }6 W* w% }
D. Most Important Aspect of Flower Care
& G O j3 P& ?. Y' e3 z2 _ E. Need for Clean Water' X2 ^ {( v. Z+ ~9 d
F. Ways of Stopping Respiration5 f6 }% q% k5 a- P3 l" B
1 Paragraph 2__________________6 z9 w( z& z6 P8 d7 s
2 Paragraph 3__________________
# t+ j0 K _! C# ^: v 3 Paragraph 4__________________& M* F+ B7 p' L* o% U
4 Paragraph 5__________________& _% \; _ ^. y% _( j$ Q% J: ?
A. by keeping its original shape and colour3 L! x( l( S- \( c9 q
B. in the life of the cut flower. s# v1 \# E1 q# A6 u
C. to produce carbon dioxide, c/ D% f+ a. U6 J
D. for as long as possible
% d0 H( x( w$ C! Y, S- I E. by controlling temperature$ k& ]: s" \( d; H' E' E7 [
F. to replace the water and solution every day- Q5 F* c6 l l$ r0 y( @
5 A few simple facts will help you keep cut flowers_______________
. r: T0 y" p( x 6 Respiration plays a key role________________
, M4 _' X5 d: K. N( _/ y7 d 7 The aging of cut flowers can be slowed down_________________
% v6 q$ d0 w* R7 s 8 Another important way to prolong the life of cut flowers is ____________________ |
发表于 2012-8-15 23:46:35
