阅读下面这篇短文，短文后有2项测试任务：(1)第23～26题要求从所给的6个选项中为第2～5段每段选择1个正确的小标题；(2)第27～30题要求从所给的6个选项中选择4个正确选项，分别完成每个句子。
Keeping Cut Flowers 1 While everybody enjoys fresh cut
flowers around their 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. 2 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 12℃ than when kept at 26℃.
Keeping freshly. harvested flowers at the right temperatures is probably the
most important aspect of flower care. 3 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. 4 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. 5 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. Paragraph 2______A. Control of Respiration