【正文】 me trees pensate for this by growing natural buttresses. These buttresses are basically tree trunks that extend out from the side of the tree and down to the ground, giving the tree additional support.Rainforest trees are dependent on bacteria that are continually producing nutrients in the ground. Rainforest bacteria and trees have a very close, symbiotic (共生的) relationship. The trees provide the bacteria with food, in the form of fallen leaves and other material, and the bacteria break this material down into the nutrients that the trees need to survive.One of the most remarkable things about rainforest plant life is its diversity. The temperate rainforests of the Pacific Northwest are mainly posed of a dozen or so tree species. A tropical rainforest, on the other hand, might have 300 distinct tree species.All Creatures, Great and SmallRainforests are home to the majority of animal species in the world. And a great number of species who now live in other environments, including humans, originally inhabited the rainforests. Researchers estimate that in a large rainforest area, there may be more than 10 million different animal species.Most of these species have adapted for life in the upper levels of the rainforest, where food is most plentiful. Insects, which can easily climb or fly from tree to tree, make up the largest group (ants are the most abundant animal in the rainforest). Insect species have a highly symbiotic relationship with the plant life in a rainforest. The insects move from plant to plant, enjoying the wealth of food provided there. As they travel, the insects may pick up the plants39。 seeds, dropping them some distance away. This helps to disperse the population of the plant species over a larger area.The numerous birds of the rainforest also play a major part in seed dispersal. When they eat fruit from a plant, the seeds pass through their digestive system. By the time they excrete (排泄) the seeds, the birds may have flown many miles away from the fruitbearing tree.There are also a large number of reptiles and mammals in the rainforest. Since the weather is so hot and humid during the day, most rainforest mammals are active only at night, dusk or dawn. The many rainforest bat species are especially well adapted for this lifestyle. Using their sonar, bats navigate easily through the mass of trees in the rainforest, feeding on insects and fruit.While most rainforest species spend their lives in the trees, there is also a lot of life on the forest floor. Great apes, wild pigs, big cats and even elephants can all be found in rainforests. There are a number of people who live in the rainforests, as well. These tribes which, up until recently, numbered in the thousands are being forced out of the rainforests at an alarming rate because of deforestation.DeforestationIn the past hundred years, humans have begun destroying rainforests at an alarming rate. Today, roughly acres of rainforest are destroyed every second. People are cutting down the rainforests in pursuit of three major resources： Land for crops Lumber for paper and other wood products Land for livestock pasturesIn the current economy, people obviously have a need for all of these resources. But almost all experts agree that, over time, we will suffer much more from the destruction of the rainforests than we will benefit.The world39。s rainforests are an extremely valuable natural resource, to be sure, but not for their lumber or their land. They are the main cradle of life on Earth, and they hold millions of unique life forms that we have yet to discover. Destroying the rainforests is parable to destroying an unknown planetwe have no idea what we39。re losing. If deforestation continues at its current rate, the world39。s tropical rainforests will be wiped out within 40 years.1. Virtually all plant and animal species on Earth can be found in tropical rainforests.2. There is not much change in the weather in the tropical rainforests all the year round.3. The largest number of rainforests in the world are located on the African continent.4. Below the canopy level of a tropical rainforest grows an overabundance of plants.5. New tree seedlings will not survive to reach the canopy level unless ________.6. Epiphytes, which form much of the under story of the rainforest, get all their water and nutrients from ________.7. Stranglers are so called because they ________ by blocking the sunlight and peting for the nutrients.8. Since rainforest bacteria and trees depend on each other for life, the relationship they form is termed ________.9. Plant species are dispersed over a large area with the help of ________.10. As we are still ignorant of millions of unique life forms in the rainforest, deforestation can be pared to the destruction of ________.Part III Listening Comprehension (35 minutes) Section ADirections: In this section, you will hear 8 short conversations and 2 long conversations. At the end of each conversation, one or more questions will be asked about what was said. Both the conversation and the questions will be spoken only once. After each question there will be a pause. During the pause, you must read the four choices marked A), B), C) and D), and decide which is the best answer. Then mark the corresponding letter on Answer Sheet 2 with a single line through the centre. 11. A) She isn39。t going to change her major. B) She plans to major in tax law. C) She studies in the same school as her brother. D) She isn39。t going to work in her brother39。s firm.12. A) She will do her best if the job is worth doing. B) She prefers a life of continued exploration. C) She will stick to the job if the pay is good. D) She doesn39。t think much of jobhopping.13. A) Stop thinking about the matter. B) Talk the drug user out of the habit. C) Be more friendly to his schoolmate. D) Keep his distance from drug addicts.14. A) The son. C) The mother. B) The father. D) Aunt Louise.15. A) Stay away for a couple of weeks. C) Look after the Jo