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Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate
the correct answer to each of the questions from 43 to 50.
Carbon dating can be used to estimate the age of any organic natural material; it has been used
successfully in archeology to determine the age of ancient artifacts or fossils as well as in a
variety of other fields. The principle underlying the use of carbon dating is that carbon is a part
of all living things on Earth. Since a radioactive substance such as carbon-14 has a known half-
life, the amount of carbon-14 remaining in an object can be used to date that object.
Carbon-14 has a half-life of 5,570 years, which means that after that number of years, half of the
carbon- 14 atoms have decayed into nitrogen-14. It is the ratio of carbon-14 in that substance
that indicates the age of the substance. If, for example, in a particular sample the amount of
carbon-14 is roughly equivalent to the amount of nitrogen-14, this indicates that around half of
the carbon-14 has decayed into nitrogen-14, and the sample is approximately 5,570 years old.
Carbon dating cannot be used effectively in dating objects that are older than 80,000 years.
When objects are that old, much of the carbon-14 has already decayed into nitrogen-14, and the
miniscule amount that is left doesn’t provide a reliable measurement of age. In the case of older
objects, other age- dating methods are available, methods which use radioactive atoms with
longer half-lives than carbon has.
Question 41: This passage is mainly about .
A. archeology and the study of ancient artifacts
B. one method of dating old objects
C. various uses for carbon
D. the differences between carbon-14 and nitrogen-14
Question 42: Which of the following is NOT true about carbon-14?
A. It and nitrogen always exist in equal amounts in any substance.
B. Its half-life is more than 5,000 years.
C. It can decay into nitrogen-14.
D. It is radioactive.
Question 43: The word “it” in paragraph I refers to .
A. carbon dating B. the age
C. any organic natural material D. archeology
Question 44: The word “underlying” in paragraph I could best be replaced by .
A. below B. requiring
C. serving as a basis for D. being studied through
Question 45: The word “roughly” in paragraph 2 is closest in meaning to .
A. precisely B. harshly C. approximately D. coarsely
Question 46: The paragraph following the passage most probably discusses .
A. what substances are part of all living things
B. how carbon-14 decay intonitrogen-14
C. why carbon-14 has such a long half-life
D. various other age-dating methods
Question 47: It is implied in the passage that .
A. carbon dating has no known uses outside of archeology
B. fossils cannot be age-dated using carbon-14
C. carbon dating could not be used on an item containing nitrogen
D. carbon-14 does not have the longest known half-life
Question 48: It can be inferred from the passage that if an item contains more carbon-14 than
nitrogen- 14, then the item is .
A. not as much as 5,570 years old
B. too old to be age-dated with carbon-14
C. too radioactive to be used by archeologists
D. more than 5.570 years old
Mark the letter A, B, C, or D on your answer sheet to indicate the sentence that best
completes each of the following exchanges.
Question 49: Two friends, Diana and Anne, are talking about Anne’s new blouse. Diana: “That
blouse suits you perfectly, Anne.”
Anne: “ .”
A. Never mind B. Don’t mention it C. Thank you D. You’re welcome
Question 50: Mary is talking to a porter in the hotel lobby. Porter: “Shall I help you with your
suitcase?”
Mary: “ ”
A. Not a chance. B. That’s very kind of you.
C. I can‘t agree more. D. What a pity!
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