托福阅读段落

TPO24-1 Lake Water

The questions become more complicated when actual volumes of water are considered: how much water enters and leaves by each route? Discovering the inputs and outputs of rivers is a matter of measuring the discharges of every inflowing and outflowing stream and river. Then exchanges with the atmosphere are calculated by finding the difference between the gains from rain, as measured (rather roughly) by rain gauges, and the losses by evaporation, measured with models that correct for the other sources of water loss. For the majority of lakes, certainly those surrounded by forests, input from overland flow is too small to have a noticeable effect. Changes in lake level not explained by river flows plus exchanges with the atmosphere must be due to the net difference between what seeps into the lake from the groundwater and what leaks into the groundwater. Note the word "net": measuring the actual amounts of groundwater seepage into the lake and out of the lake is a much more complicated matter than merely inferring their difference.

2. The word gains in the passage is closest in meaning to

A results

B increases

C resources

D savings

3. Which of the following can be inferred from paragraph 2 about the movement of water into a lake?

A Heavy rain accounts for most of the water that enters into lakes.

B Rainfall replaces approximately the amount of water lost through evaporation.

C Overland flow into lakes is reduced by the presence of forests.

D Seepage has a smaller effect on water level than any other input.

4. Why does the author use the phrase Note the word "net" in the passage?

A To emphasize the impact of seepage on water levels

B To point out that seepage is calculated differently from river flows and atmospheric exchanges

C To compare the different methods of calculating seepage

D To emphasize the difficulty of obtaining specific values for seepage inputs and outputs

TPO24-3Moving into Pueblos

Given all the disadvantages of living in aggregated towns, why did people in the thirteenth century move into these closely packed quarters? For transitions of such suddenness, archaeologists consider either pull factors (benefits that drew families together) or push factors (some external threat or crisis that forced people to aggregate). In this case, push explanations dominate.

5. According to paragraph 3, which of the following was one of the consequences of

increasing population densities?

A People were increasingly crowded into collections of large housing units.

B People stopped planting crops that have relatively low yields.

C Domestic buildings were pushed beyond the canyon limits.

D The natural landscape was destroyed.

♦Population growth is considered a particularly influential push. After several generations of population growth, people packed the landscape in densities so high that communal pueblos may have been a necessary outcome. Around Sand Canyon, for example, populations grew from 5 -12 people per square kilometer in the tenth century to as many as 30 - 50 by the 1200s. As densities increased, domestic architecture became larger, culminating in crowded pueblos. Some scholars expand on this idea by emphasizing a corresponding need for arable land to feed growing numbers of people: construction of small dams, reservoirs, terraces, and field houses indicates that farmers were intensifying their efforts during the 1200s. Competition for good farmland may also have prompted people to bond together to assert rights over the best fields.

6. Which of the sentences below best expresses the essential information in the highlighted sentence in the passage?Incorrect choices change the meaning in important ways or leave out essential information.

A Some scholars even claim that the intensification of farmers' various efforts during the 1200s led to further population growth and the consequent need for more arable land.

B Evidence of intensifying agriculture in the 1200s indicates a need to feed a larger population and so extends the argument that a growing population was the cause of the move to pueblos.

C During the 1200s, farmers met the demand for more arable land, but they also succeeded in cultivating existing land more intensively with the help of agricultural construction projects.

D Some scholars feel strongly that the construction of small dams, reservoirs, terraces, and field houses in the thirteenth century is independent evidence for growth in the number of people.

TPO25-2 The Decline of Venetian Shipping

This decline can be seen clearly in the changes that affected Venetian shipping and trade. First, Venice’s intermediary functions in the Adriatic Sea, where it had dominated the business of shipping for other parties, were lost to direct trading. In the fifteenth century there was little problem recruiting sailors to row the galleys (large ships propelled by oars): guilds (business associations) were required to provide rowers, and through a draft system free citizens served compulsorily when called for. In the early sixteenth century the shortage of rowers was not serious because the demand for galleys was limited by a move to round ships (round-hulled ships with more cargo space), with required fewer rowers. But the shortage of crews