托福阅读真题及答案：TPO1（GROUNDWATER）_第3页

Paragraph 6:

　　Paragraph 7:

　　10. According to paragraphs 6 and 7, why is basalt unlike most crystalline forms of rock?

　　○It is unusually solid

　　○It often has high porosity.

　　○It has a low proportion of empty space.

　　○It is highly permeable.

　　11. What is the main purpose of paragraph 7?

　　○To explain why water can flow through rock

　　○To emphasize the large amount of empty space in all rock

　　○To point out that a rock cannot be both porous and permeable

　　○To distinguish between two related properties of rock

　　Paragraph 9:

　　12. 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.

　　○Surface tension is not strong enough to retain drops of water in rocks with large pores but it strong enough to hold on to thin films of water in rocks with small pores.

　　○Water in rocks is held in place by large pores and drains away from small size pores through surface tension.

　　○Small pores and large pores both interact with surface tension to determine whether a rock will hold water as heavy drops or as a thin film.

　　○If the force of surface tension is too weak to hold water in place as heavy drops, the water will continue to be held firmly in place as a thin film when large pores exist.

　　Paragraph 8:

　　13. Look at the four squares [█] that indicate where the following sentence could be added to the passage.

　　What, then, determines what proportion of the water stays and what proportion drains away?

　　Where would the sentence best fit? Click on a square to add the sentence to the passage.

　　一想到新托福，就想到咱老无。

　　14. Directions: An introductory sentence for a brief summary of the passage is provided below. Complete the summary by selecting the THREE answer choices that express the most important ideas in the passage. Some sentences do not belong in the summary because they express ideas that are not presented in the passage or are minor ideas in the passage. This question is worth 2 points.

　　Much of the ground is actually saturated with water.

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　　Answer choices

　　○Sediments that hold water were spread by glaciers and are still spread by rivers and streams.

　　○Water is stored underground in beds of loose sand and gravel or in cemented sediment.

　　○The size of a saturated rock’s pores determines how much water it will retain when the rock is put in a dry place.

　　○Groundwater often remains underground for a long time before it emerges again.

　　○Like sandstone, basalt is a crystalline rock that is very porous.

　　○Beds of unconsolidated sediments are typically located at inland sites that were once underwater.