3. It can be inferred from the passage that paleoclimatologists have concluded which of the following on the basis of their study of snow-line elevations in the southwestern United States？
（A） There is usually more precipitation during an ice age because of increased amounts of evaporation.
（B） There was less precipitation during the last ice age than there is today.
（C） Lake levels in the semiarid southwestern United States were lower during the last ice age than they are today.
（D） During the last ice age， cooler weather led to lower lake levels than paleoclimatologists had previously assumed.
（E） The high lake levels during the last ice age may have been a result of less evaporation rather than more precipitation.
4. Which of the following would be the most likely topic for a paragraph that logically continues the passage？
（A） The kinds of plants normally found in arid regions
（B） The effect of variation in lake levels on pollen distribution
（C） The material best suited to preserving signals of climatic changes
（D） Other criteria invoked by paleoclimatologists when choosing a method to determine past climatic
conditions
（E） A third method for investigating past climatic conditions
5. The author discusses lake levels in the southwestern United States in order to
（A） illustrate the mechanics of the relationship between lake level， evaporation， and precipitation
（B） provide an example of the uncertainty involved in interpreting lake levels
（C） prove that there are not enough ancient lakes with which to make accurate correlations
（D） explain the effects of increased rates of evaporation on levels of precipitation
（E） suggest that snow-line elevations are invariably more accurate than lake levels in determining rates of precipitation at various points in the past
6. It can be inferred from the passage that an environmental signal found in geological material would not be useful to paleoclimatologists if it
（A） had to be interpreted by modern chemical means
（B） reflected a change in climate rather than a long- term climatic condition
（C） was incorporated into a material as the material was forming
（D） also reflected subsequent environmental changes
（E） was contained in a continental rather than a marine sequence
7. According to the passage， the material used to determine past climatic conditions must be widespread for which of the following reasons？
Ⅰ。Paleoclimatologists need to make comparisons between periods of geological history.
Ⅱ。 Paleoclimatologists need to compare materials that have supported a wide variety of vegetation.
Ⅲ。 Paleoclimatologists need to make comparisons with data collected in other regions.
（A） Ⅰ only
（B） Ⅱ only
（C） Ⅰ and Ⅱ only
（D） Ⅰ and Ⅲ only
（E） Ⅱ and Ⅲ only
8. Which of the following can be inferred from the passage about the study of past climates in arid and semiarid regions？
（A） It is sometimes more difficult to determine past climatic conditions in arid and semiarid regions than in temperate regions.
（B） Although in the past more research has been done on temperate regions， paleoclimatologists have recently turned their attention to arid and semiarid regions.
（C） Although more information about past climates can be gathered in arid and semiarid than in temperate regions， dating this information is more difficult.
（D） It is difficult to study the climatic history of arid and semiarid regions because their climates have tended to vary more than those of temperate regions.
（E） The study of past climates in arid and semiarid regions has been neglected because temperate regions support a greater variety of plant and animal life.
Keys： ECEEB DDA
责任编辑：wangpeng6151
