PASSAGE 22

PASSAGE 22
Although only a small percentage of the electromagnetic radiation that is emitted by the Sun is
ultraviolet (UV) radiation, the amount that is emitted would be enough to cause severe damage to most
forms of life on Earth were it all to reach the surface of the Earth. Fortunately, all of the Sun’s ultraviolet
radiation does not reach the Earth because of a layer of oxygen, called the ozone layer encircling the
Earth in the stratosphere at an altitude of about 15 miles above the Earth. The ozone layer absorbs much
of the Sun’s ultraviolet radiation and prevents it from reaching the Earth.
Ozone is a form of oxygen in which each molecule consists of three atoms (O3) instead of the two
atoms (O2) usually found in an oxygen molecule. Ozone forms in the stratosphere in a process that is
initiated by ultraviolet radiation from the Sun. UV radiation from the Sun splits oxygen molecules with
two atoms into free oxygen atoms, and each of these unattached oxygen atoms then joins up with an
oxygen molecule to form ozone. UV radiation is also capable of splitting up ozone molecules; thus, ozone
is constantly forming, splitting, and reforming in the stratosphere. When UV radiation is absorbed during
the process of ozone formation and reformation, it is unable to reach Earth and cause damage there.
Recently, however, the ozone layer over parts of the Earth has been diminishing. Chief among the
culprits in the case of the disappearing ozone, those that are really responsible, are the
chlorofluorocarbons (CFCs). CFCs meander up from Earth into the stratosphere, where they break down
and release chlorine. The released chlorine reacts with ozone in the stratosphere to form chlorine
monoxide (CIO) and oxygen (O2). The chlorine then becomes free to go through the cycle over and over
again. One chlorine atom can, in fact, destroy hundreds of thousands of ozone molecules in this
repetitious cycle, and the effects of this destructive process are now becoming evident.
Question 1. According to the passage, ultraviolet radiation from the Sun ____________
A. is causing severe damage to the Earth's ozone layer
B. is only a fraction of the Sun's electromagnetic radiation
C. creates electromagnetic radiation
D. always reaches the Earth
Question 2. The word “encircling” in paragraph 1 is closest in meaning to____________
A. attacking

B. raising

C. rotating

D. surrounding

Question 3. It is stated in the passage that the ozone layer____________
A. enables ultraviolet radiation to reach the Earth
B. reflects ultraviolet radiation
C. shields the Earth from a lot of ultraviolet radiation
D. reaches down to the Earth
Question 4. The pronoun “it” in paragraph 2 refers to____________
A. radiation

B. process

C. formation

D. damage

Question 5. The word “culprits'' in paragraph 3 is closest in meaning to which of the following?
A. Guilty parties

B. Detectives

C. Group members

D. Leaders

Question 6. According to the passage, what happens after a chlorine molecule reacts with an ozone
molecule?
A. The ozone breaks down into three oxygen atoms.

B. Two different molecules are created.
C. The two molecules combine into one molecule.


D. Three distinct molecules result.
Question 7. The paragraph following the passage most likely discusses____________
A. the negative results of the cycle of ozone destruction
B. where chlorofluorocarbons (CFCs) come from
C. the causes of the destruction of ozone molecules
D. how electromagnetic radiation is created
ĐÁP ÁN
1-B

2-D

6-B

7-A

3-C

4-A

5-A

LỜI GIẢI CHI TIẾT
Question 1:
Theo đoạn văn, tia cực tím từ mặt trời ..............
A. gây ra thiệt hại nghiêm trọng đối với tầng ôzôn của trái đất
B. chỉ là một phần nhỏ của bức xạ điện từ của mặt trời

C. tạo ra bức xạ điện từ
D. luôn luôn đến Trái đất
Dẫn chứng: Although only a small percentage of the electromagnetic radiation that is emitted by the Sun
is ultraviolet (UV) radiation
Question 2:
Từ "bao vây" trong đoạn 1 có ý nghĩa gần nhất với ................
A. attacking: tấn công
B. raising: tăng lên
C. rotating: xoay quanh
D. surrounding: xung quanh
Question 3:
Trong đoạn văn nói rằng tầng ơzơn ...............
A. Cho phép bức xạ cực tím đến Trái đất
B. phản xạ tia cực tím
C. che chắn cho trái đất khỏi rất nhiều tia cực tím
D. bức xạ lên xuống Trái Đất
Dẫn chứng: Fortunately, all of the Sun’s ultraviolet radiation does not reach the Earth because of a layer
of oxygen, called the ozone layer encircling the Earth in the stratosphere at an altitude of about 15 miles
above the Earth.
Question 4:
Đại từ "nó" trong đoạn 2 nói đến ...................
A. Bức xạ
B. Tiến trình
C. Sự hình thành


D. tổn hại
Dẫn chứng: When UV radiation is absorbed during the process of ozone formation and reformation, it is
unable to reach Earth and cause damage there.
Question 5:

Từ "culprits" trong đoạn 3 có ý nghĩa gần nhất với câu nào dưới đây?
A. Các bên phạm tội
B. Các nhà thám tử
C. Các thành viên của nhóm
D. Các nhà lãnh đạo
Culprit: tội phạm
Question 6:
Theo đoạn văn, những gì xảy ra sau khi một phân tử clo phản ứng với một phân tử ozon?
A. ozon phân hủy thành ba nguyên tử oxy.
B. Hai phân tử khác nhau được tạo ra.
C. Hai phân tử này kết hợp thành một phân tử.
D. Ba kết quả phân tử khác biệt.
Dẫn chứng: The released chlorine reacts with ozone in the stratosphere to form chlorine monoxide (ClO)
and oxygen (O2).
Question 7:
Đoạn văn sau đoạn văn có nhiều khả năng thảo luận ..................
A. các kết quả âm của chu trình phá hủy ozone
B. nơi chlorofluorocarbons (CFCs) đến từ
C. các nguyên nhân phá hủy các phân tử ozon
D. làm thế nào bức xạ điện từ được tạo ra
Dẫn chứng: the effects of this destructive process are now becoming evident.