戴爾美語練功坊 托福閱讀(11/10) - 英檢

戴爾美語練功坊 托福閱讀(11/10)
Radon
Radon is a radioactive gas that is invisible and odorless.
It forms during the decay of uranium-238, and it decaying,
itself produces solid heavy metal radioactive particles of polonium,
lead, and bismuth. The parent element, uranium, is distributed in
rocks and soils in many regions of the world, although usually in
negligible amounts. However, concentrations of this element occur
in certain rocks, and under certain conditions it is dissolved by
underground water and carried over great distances before seeping
into other rocks and soils.

→ Since radon is a gas, it can move from the ground into the air,
where it is dispersed by the wind. If it infiltrates the buildings,
however, it can build up over time and lead to serious health problems.
In fact, the radon itself is chemically inert and so does not enter into
chemical reactions with other substances. It is readily dissolved in
blood and circulates through the body until it is expelled usually
before it has had time to decay. The health problems relevant to
radon activity arise from the radioactive products of its disintegration,
mentioned above.

→ The products of the decay process, especially polonium-218 and
polonium-214, emit radiation, which kills and damages living cells,
causing genetic mutations and cancer. These radon progeny are
not dispersed harmlessly like radon itself but accumulate as the
radon decays. Outside the body, these solid materials can attach
themselves to dust particles and surfaces throughout a building and
then be inhaled. The decay products can also stick to tobacco
leaves during growth and then enter the body when tobacco
is smoked. Inside the body these dangerous by- products of
radon become lodged in lung tissue and the bronchial tubes.
As these decay, they emit alpha and beta particles and gamma rays.
Of these, the alpha particles can do the most damage since they are
the bulkiest of the three and therefore cannot penetrate very far
into living tissue. Because of this relative immobility,
concentrations of the particle form and damage cells in the
immediate area. Beta particles and gamma rays are less dangerous
sincethey travel further and are less concentrated in the tissues.
The primary way that radon penetrates building is through
foundations. It enters through cracks in basement floors, drains,
loose-fitting pipes, and exposed soil areas. Radon also finds its
way into water, although if the water is exposed to the
atmosphere or agitated, the radon disperses into the air.
Because of this, concentrations of this uranium daughter are not
high in rivers, but water drawn from underground sources into
homes can have elevated levels.

The chief health risk from inhaling radon or its daughter
products is lung cancer. (A)■ Scientists have concluded that
exposure to this carcinogen is the second leading cause of this
disease in the United States. (B)■ Major scientific organizations
believe it contributes to approximately 12 percent of the incidence
in the United States alone. It is true that some research has cast
doubt on the likelihood of residential radon accumulations
contributing to cancer rates. (C)■ Other larger scale studies
contradict the neutral findings. For example, a recent study of
68,000 underground miners who were exposed to high levels of
radon shows that they are five times more likely to die of lung
cancer than the general population. (D)■ Smokers, whose
incidence of lung cancer is significantly higher than nonsmoking
population, are even more at risk if they are exposed to high
levels of radon.

→ It is now possible to have buildings tested for radon
accumulation. In an average home, this is about 1.3 picocuries
per liter, which is considered an acceptable although not a totally
safe level. If these levels are above 4 picocuries per liter of air,
then homeowners are advised to reduce the amount seeping into
the living space. This can be achieved through various
means including concrete sealing and the installation of active
ventilation systems. It is not possible to completely eradicate
traces of radon since the natural outdoors level averages 0.4
picocuries per liter, but minimizing the amount is a prudent
preventative measure.
? picocurie: a level of radiation activity
1. The word" this element " in the passage refers to
(A) lead (B) radon (C) uranium (D) polonium
2. The word " seeping " in the passage is closest in meaning to
(A) leaking (B) spilling (C) releasing (D) erupting
3. In paragraph 2, what can be inferred about the relationship of
radon and health problems?
(A) The gas has to have time to decay in order to cause health problems.
(B) Since radon is chemically inert, it cannot lead to health problems.
(C) As a gas, radon disperses in the wind and consequently isn't
a health problem.
(D) The gas has to disintegrate before it can seep into buildings.

Paragraph 2 is marked with an arrow (→)
4. According to the passage, health problems associated with radon
are caused by
(A) radioactive uranium (B) buildup of certain heavy metals
(C) decaying gases (D) some chemical reactions


5. According to the paragraph 3, the reason why some products of
decay cause damage is that
(A) they emit gamma rays.
(B) they cannot penetrate living tissue very deeply.
(C) they are highly mobile.
(D) they seep into houses and form concentrations of radiation.

6. According to the passage, all of the following are true about radon
EXCEPT
(A) It is invisible. (B) It is radioactive.
(C) It cannot be smelled. (D) It cannot be detected.

7. It can be understood from paragraph 6 that
(A) reducing the amount of radon in your home is pointless because
of the amount of radon outside.
(B) even though it is possible to test buildings for radon accumulation,
it is not possible to minimize the level of radiation activity.
(C) the use of concrete sealing and active ventilation systems can
reduce the amount of radon to an acceptable level.
(D) using concrete sealing and installing active ventilation systems
reduces the amount of usable living space.

8. The word " prudent " in the passage is closest in meaning to
(A) sensible (B) necessary (C) practical (D) realistic

9. Look at the four squares [(A) ■ (B)■ (C)■ (D)■] that indicate where
the following sentence could be added to the passage. Circle the letter
that shows the point where you would insert this sentence.
But this research has been criticized for being based on too few subjects.
Where would the sentence best fit?
Click on a square (■) to add the sentence to the passage.

10. 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.
Radon can seep into a building, where its decay products can lead to
health problems.

●__________________________________________________________
●__________________________________________________________
●__________________________________________________________

Answer Choices:
(A) Although radon can enter a building in many different ways, it also
escapes through cracks in the foundations.
(B) Concentrations of the radon by-products attach themselves to
particles in the air inside buildings and are breathed into the lungs.
(C) People who smoke or work in mines are at greater risks of getting
lung cancer that is related to alpha particles than those who work in
buildings.
(D) The by-product alpha particles are too heavy to disperse through
the tissues, so they accumulate in the lungs where they kill or damage
lung cells.
(E) Radon does not cause lung cancer because it is chemically inert
and therefore readily dissolves in the blood, where it eventually is
expelled from the body.
(F) Preventative measures can be taken to reduce the amount of
exposure to radon in living spaces, but it is not possible to completely
eliminate the gas from the atmosphere.
TOEFL Reading: 閱讀作答之要領
(1) 審視題幹 → (2) 搜尋核心關鍵字詞 (keywords)
→ (3)原文定位 (positioning /locating) → (4) 判讀分析.


1. 答案: C
解析: 此題屬於指代關係題(Reference), 根據題意this element指的是
radon 之母元素 --- uranium.
The parent element, uranium, is distributed in rocks and soils in many
regions of the world, although usually in negligible amounts. However,
concentrations of this element occur in certain rocks..

2. 答案: A
解析: 此題屬於單字題(Vocabulary), seeping (滲出/漏)與 leaking同義
; spill (灑/ 溢出) ; release (釋放) ; erupt (爆炸).

3. 答案: A
解析: 此題屬於推論題(Inference).
根據題意,關於radon 與健康問題之間關係;關鍵字為 health problem,
定位第二段, If it infiltrates the buildings, however, it can build up
over time and lead to serious health problems. Radon會隨時間漸漸積累,
因而導致健康問題.

4. 答案: B
解析: 此題屬於事實細節題 (Factual & Detailed Information).
根據題意, 關於導致Radon 相關之健康問題為何? The health
problems relevant to radon activity arise from the radioactive products
of its disintegration, mentioned above.
文意敘述Radon 所引發之健康問題乃由於它分解出放射性物質所導致,
如同上述一般. 故而返回上段首句 : Radon is a radioactive gas that
is invisible and odorless. It forms during the decay of uranium-238,
and it decaying, itself produces solid heavy metal radioactive particles
of polonium, lead, and bismuth. 判讀radon 分裂產生重金屬物質---
polonium(釙), lead (鉛), 及bismuth (鉍).

5. 答案: B
解析: 此題屬於事實細節題 (Factual & Detailed Information).
根據題意, 為何某些衰變之後產物導致傷害?
Key word為damage ,原文定位--- Of these, the alpha particles can do
the most damage since they are the bulkiest of the three and therefore cannot penetrate very far into living tissue.

6. 答案: D
解析: 此題屬於否定事實題 (Negative Factual Information).
根據題意有關radon 之敘述何者為非.
原文首段-- Radon is a radioactive gas that is invisible and odorless.
尾段--- It is now possible to have buildings tested for radon accumulation.
Radon 可以透過儀器偵測出, 並非無法檢出.

7. 答案: C
解析: 此題屬於事實細節題 (Factual & Detailed Information).
If these levels are above 4 picocuries per liter of air, then homeowners
are advised to reduce the amount seeping into the living space.
This can be achieved through various means including concrete sealing
and the installation of active ventilation systems.
符合選項C ---利用混凝土密封及通風系統可以有效降低radon至
可接受之範圍.
8. 答案: A
解析: 此題屬於單字題(Vocabulary) , prudent (謹慎的; 精明的)與
sensible (明智的) 同義.

9. 答案: C
解析: 此題屬於句子插入題 (Sentence Insertion).
運用技巧 :
(1) succession 承接原則(2) transition轉折原則(3) pronoun 代名詞原則.
But this research has been criticized for being based on too few subjects.
(然而該項研究之基礎由於過少研究對象而遭致批判.)
This research / subjects 為定位詞 , But 為轉承語詞, It is true that
some research has cast doubt on the likelihood of residential radon
accumulations contributing to cancer rates.
(C) ■ Other larger scale studies contradict the neutral findings.
For example, a recent study of 68,000 underground miners who were
exposed to high levels of radon shows that they are five times more
likely to die of lung cancer than the general population.
C之前提及某項研究,後旋及提出其他大規則研究(以68000研究對象
加入此研究) 亦駁斥此發現.因而確認適當之位置插入於 C.

10. 答案: B D F
解析: 此題屬於文意摘要題 (Prose Summary)
引導句為 Radon can seep into a building, where its decay products
can lead to health problems.(radon 滲入建築物內, 在此間它的衰變
物質導致健康問題.)摘要所選擇之要點皆須以 radon 為主軸, 並且針
對其所引發之相關健康問題為答案. 更甚者, 原文之結論段之敘述為
全文綜論亦應納入全文概要論述.
(B) Concentrations of the radon by-products attach themselves to
particles in the air inside buildings and are breathed into the lungs.
(D) The by-product alpha particles are too heavy to disperse through
the tissues, so they accumulate in the lungs where they kill or damage
lung cells.
(F) Preventative measures can be taken to reduce the amount of
exposure to radon in living spaces, but it is not possible to completely
eliminate the gas from the atmosphere.

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