托福阅读真题：TPO 1(Timberline Vegetation on Mountains)原文及答案

　　1. The word “dramatic” in the passage is closest in meaning to

　　○gradual

　　○complex

　　○visible

　　○striking

　　2. Where is the lower timberline mentioned in paragraph 1 likely to be found?

　　○In an area that has little water

　　○In an area that has little sunlight

　　○Above a transition area

　　○On a mountain that has on upper timberline.

　　3. Which of the following can be inferred from paragraph 1 about both the upper and lower timberlines?

　　○Both are treeless zones.

　　○Both mark forest boundaries.

　　○Both are surrounded by desert areas.

　　○Both suffer from a lack of moisture.

　　Paragraph 2: The upper timberline, like the snow line, is highest in the tropics and lowest in the Polar Regions. It ranges from sea level in the Polar Regions to 4,500 meters in the dry subtropics and 3,500-4,500 meters in the moist tropics. Timberline trees are normally evergreens, suggesting that these have some advantage over deciduous trees (those that lose their leaves) in the extreme environments of the upper timberline. There are some areas, however, where broadleaf deciduous trees form the timberline. Species of birch, for example, may occur at the timberline in parts of the Himalayas.

　　4. Paragraph 2 supports which of the following statements about deciduous trees?

　　○They cannot grow in cold climates.

　　○They do not exist at the upper timberline.

　　○They are less likely than evergreens to survive at the upper timberline.

　　○They do not require as much moisture as evergreens do.

　　Paragraph 3: At the upper timberline the trees begin to become twisted and deformed. This is particularly true for trees in the middle and upper latitudes, which tend to attain greater heights on ridges, whereas in the tropics the trees reach their greater heights in the valleys. This is because middle- and upper- latitude timberlines are strongly influenced by the duration and depth of the snow cover. As the snow is deeper and lasts longer in the valleys, trees tend to attain greater heights on the ridges, even though they are more exposed to high-velocity winds and poor, thin soils there. In the tropics, the valleys appear to be more favorable because they are less prone to dry out, they have less frost, and they have deeper soils.

　　5. The word “attain” in the passage is closest in meaning to

　　○require

　　○resist

　　○achieve

　　○endure

　　6. The word “they” in the passage refers to

　　○valleys

　　○trees

　　○heights

　　○ridges

　　7. The word “prone” in the passage is closest in meaning to，http://bj.xhd.cn/toefl/来源：北京新航道托福培训

　　○adapted

　　○likely

　　○difficult

　　○resistant

　　8. According to paragraph 3, which of the following is true of trees in the middle and upper latitudes?

　　○Tree growth is negatively affected by the snow cover in valleys.

　　○Tree growth is greater in valleys than on ridges.

　　○Tree growth on ridges is not affected by high-velocity winds.

　　○Tree growth lasts longer in those latitudes than it does in the tropics.