[单项选择]Many scientists are so convinced of the benefits of challenging the brain that they are putting it into practice in their lives.（）
A. 许多科学家都确信，在他们的生活中，经常练习挑战大脑，就会带来效益。
B. 许多科学家都对勤于动脑的益处确信不移，他们在自己的生活中也努力实践着。
C. 许多科学家都如此确信挑战大脑会带来利益，他们的实际生活证实了这一点。
D. 许多科学家都相信，他们生命中所实践的就是对人的大脑挑战，这种挑战是有益的。

[单项选择]

Many scientists today are convinced that life exists elsewhere in the universe—life probably much like that on our own planet. They reason in the following way.
As far as astronomers can determine, the entire universe is built of the same matter. They have no reason to doubt that matter obeys the same laws in every part of the universe. Therefore, it is reasonable to guess that other stars, with their own planets, were born in the same way as our own solar system. What we know of life on earth suggests that life will arise wherever the proper conditions exist.
Life requires the right amount and kind of atmosphere. This eliminates all those planets in the universe that are not about the same size and weight as the earth. A smaller planet would lose its atmosphere, a larger one would hold too much of it.
Life also required a steady supply of heat and light. This eliminates double stars, or stars that flare up suddenly. Only single stars that are steady
A. has different laws
B. has one common law
C. shares the same laws
D. shares no common law

[单项选择]A. Scientists are convinced that most animals cannot adapt to changes in climate.
B. Certain animals are more adaptable as they can live in extreme conditions.
C. Climate changes are responsible for the disappearance of some species.
D. Some species can move to the new surroundings in case of climate changes.

[单项选择]Most people recognize the many benefits of learning a foreign language : you can travel to foreign countries and feel comfortable, be a more productive and enticing employee in today’s competitive job market, and immerse yourself in the vast cultures that surround you. Scientific studies have even shown that learning a new language helps to keep memories sharp and naturally enhances overall brain function. But did you know that you can learn a new language in as little as 10 days The Pimsleur Approach to learning new languages helps users pick up new languages quickly. Even the FBI and National Security Agency have purchased the Pimsleur Approach.
Dr. Pimsleur, a Ph. D. and specialist in the field of applied linguistics, devoted his life and career to learning languages and understanding the psychology of language acquisition. He recognized through extensive research that effective communication in any language depends on mastery of a relatively limited number of words. And, tryin
A. $ 19.95.
B. $ 10.
C. $ 9.98.
D. $ 9.9.