在自然保护区中的核心区内，只准从事科学研究活动，禁止其他旅游及生产经营活动。()
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消费者的公平交易权主要体现在：在购买商品或者接受服务时，有权获得质量保障、价格合理、计量正确等公平交易的条件。()
A. 正确
B. 错误
What do Ho's words "Bear in mind that undetectable does not equal absent" mean？
AIDS virus can exist in the blood without being detected.
B. AIDS virus is undetectable in the blood.
C. NO AIDS virus can be detected in the blood.
D. No virus found in the blood means no AIDS.
One of the Price's findings (Paragraph 2) about the particles of the air is that ______.
A. they contain more pollutants than normal particles
B. they move much faster in high altitudes than in low altitudes
C. they are finer and lighter than normal particles
D. their ability to reflect light is much than stronger
Which of the statements is closest in meaning to the sentence" we expect that sources in Europe will contribute less than Asian sources."？
A. Pollution is expected to be less serious in Europe than in Asia.
B. Pollution is studied in more depth in Europe than in Asia.
C. Pollutants coming from Europe are not the main source of pollution in North America.
D. Pollutants coming from Europe are the main source of pollution in North America.
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