托福阅读常考话题及练习题推荐三：地下水（2）

1托福阅读常考话题：地下水练习题

Paragraph 1: To understand the ancient Mayan people who lived in the area that is today southern Mexico and Central America and the ecological difficulties they faced, one must first consider their environment, which we think of as "jungle" or "tropical rainforest." This view is inaccurate, and the reason proves to be important. Properly speaking, tropical rainforests grow in high-rainfall equatorial areas that remain wet or humid all year round. But the Maya homeland lies more than sixteen hundred kilometers from the equator, at latitudes 17 to 22 degrees north, in a habitat termed a "seasonal tropical forest." That is, while there does tend to be a rainy season from May to October, there is also a dry season from January through April. If one focuses on the wet months, one calls the Maya homeland a "seasonal tropical forest"; if one focuses on the dry months, one could instead describe it as a "seasonal desert."

1. Why does the author call the Mayan homeland both a “seasonal tropical forest” and "seasonal desert”?

A. To illustrate how the climate of the Mayan homeland varied from region to region

B. To explain how the climate of the Mayan homeland is similar to that of a jungle or tropical rainforest

C. To emphasize the vast size of the area that comprised the Mayan homeland in ancient times

D. To make the point that the Mayan homeland is climatically more complex than is generally assumed

Paragraph 2: From north to south in the Yucatan Peninsula, where the Maya lived, rainfall ranges from 18 to 100 inches (457 to 2,540 millimeters) per year, and the soils become thicker, so that the southern peninsula was agriculturally more productive and supported denser populations. But rainfall in the Maya homeland is unpredictably variable between years; some recent years have had three or four times more rain than other years. As a result, modern farmers attempting to grow corn in the ancient Maya homelands have faced frequent crop failures, especially in the north. The ancient Maya were presumably more experienced and did better, but nevertheless they too must have faced risks of crop failures from droughts and hurricanes.

2. Which of the following is NOT mentioned in paragraph 2 as a difference between the northern and southern Yucatan Peninsula?

A. The annual rainfall was greater in the south.

B. The population density was lower in the north.

C. Agricultural productivity was greater in the south

D. Rainfall was more unpredictable and variable in the south.

3. Which of the following statements about ancient and modem agriculture in the Yucatan Peninsula is supported by paragraph 2?

A. Modern agricultural methods have solved many of the ancient problems of farming in the Yucatan Peninsula.

B. Ancient Mayan farmers may have been somewhat more successful at farming in the Yucatan Peninsula than farmers are today.

C. Farming today is easier than in the past because environmental changes in the Yucatan Peninsula have increased available rainfall

D. The Yucatan soils in which ancient farmers worked were richer, more productive, and thicker than they are today.

Paragraph 3: Although southern Maya areas received more rainfall than northern areas, problems of water were paradoxically more severe in the wet south. While that made things hard for ancient Maya living in the south, it has also made things hard for modern archaeologists who have difficulty understanding why ancient droughts caused bigger problems in the wet south than in the dry north. The likely explanation is that an area of underground freshwater underlies the Yucatan Peninsula, but surface elevation increases from north to south, so that as one moves south the land surface lies increasingly higher above the water table. In the northern peninsula the elevation is sufficiently low that the ancient Maya were able to reach the water table at deep sinkholes called cenotes, or at deep caves. In low-elevation north coastal areas without sinkholes, the Maya would have been able to get down to the water table by digging wells up to 75 feet (22 meters) deep. But much of the south lies too high above the water table for cenotes or wells to reach down to it. Making matters worse, most of the Yucatan Peninsula consists of karst, a porous sponge-like limestone terrain where rain runs straight into the ground and where little or no surface water remains available.

4. The word “paradoxically” in the passage is closest in meaning to

A. usually

B. surprisingly

C. understandably

D. predictably

5. The phrase “The likely explanation” in the passage refers to the explanation for why

A. the southern Maya areas received more rainfall than the northern areas

B. modern archaeologists have difficulty understanding ancient droughts

C. water problems were most severe in the wet south

D. land surface in the south is so high above the water table

6. Which of the following statements about the availability of water in the Mayan homeland is supported by paragraph 3?

A. The construction of wells was an uncommon practice in both the north and the south because it was too difficult to dig through the karst.

B. In most areas in the north and the south, rainwater was absorbed directly into the porous karst.

C. The water table was an important resource for agriculture in both the north and the south of the Yucatan Peninsula.

D. The lack of surface water in both the north and the south was probably due to the fact that most of it was quickly used up for agricultural purposes.

7. According to paragraph 3, why was the southern Mayan homeland hard to farm?

A. The presence of numerous sinkholes and wells interfered with farming.

B. Southern soil lacked the depth crops needed for growth.

C. Underground water was too far below the surface to reach.

D. The presence of karst caused frequent flooding.