The essential idea of the evolutionary cosmology is that there was a beginning—a moment of creation at which the universe came into existence in a hot, violent explosion—the Big Bang. In the beginning, the universe was very hot, very dense, and very tiny. As the explosion evolved, the temperature dropped, the distribution of matter and energy thinned, and the universe expanded. From the current observed rate of expansion, we conclude that the creation event occurred between ten and twenty billion years ago.

　　4. The word “essential” in the passage is closet in meaning to

　　A. familiar

　　B. new

　　C. fundamental

　　D. controversial

　　5. According to paragraph 3, which of the following is NOT a feature of the Big Bang cosmology?

　　A. A sudden, hot explosion of the universe

　　B. A reduction in the density of matter over time

　　C. A significant rise in temperature over time

　　D. An expansion of the universe

　　Paragraph 4

　　The steady-state theory is based on an idea called the “perfect cosmological principle.” It is “perfect” in that it maintains that the universe is uniform not only in space but in time. Thus it is the hypothesis that the large-scale universe has always been the way it is now and will be this way forever in the future. This view is consistent with philosophical approaches that reject the notion of an absolute beginning of the universe as unacceptable. The steady-state universe would have no beginning and no end.

　　6. The word “notion” in the passage is closet in meaning to

　　A. nature

　　B. argument

　　C. question

　　D. idea

　　7. Why does the author state that “The steady-state universe would have no beginning and no end.”?

　　A. To present evidence against the steady-state view of the universe

　　B. To clarify why the steady-state view is attractive to certain philosophical notion approaches

　　C. To contrast cosmology with philosophy

　　D. To indicate that the steady-state view is the most accepted view among cosmologists

　　Paragraph 5

　　In an expanding universe, the galaxies move away from each other, spreading matter more thinly over space. On the other hand, the perfect cosmological principle requires that the density of matter in the universe remain constant over time. To make the steady-state theory compatible with the expanding universe, its proponents introduced the notion of continuous creation. As the universe expands and the galaxies move farther apart, new matter—in the form of hydrogen—is introduced into the universe. The rate at which the hypothesized new matter is created is far too small for this creation to be detected with available instruments, but continuous creation provides just enough matter to form new stars and galaxies that fill in the space left by the old ones. Thus in the steady-state universe there is evolution of stars and galaxies, but the general character and the overall density of the universe remains unchanged over time. In this special sense, the steady-state universe itself does not evolve.

　　8. The word “compatible” in the passage is closet in meaning to

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