19．Scientists said on Thursday they have for the first time detected gravitational （引力的） waves，ripples （涟波） in space and time hypothesized （假设） by physicist Albert Einstein a century ago，in a landmark discovery that opens a new window for studying the cosmos．
Discovering gravitational waves would be a huge deal for physics，cosmology，and our understanding of the universe at large．But if you're not a scientist studying one of the mentioned fields，it's possible you've never heard of these mysterious ripples．So what are gravitational waves and why is the discovery so significant？
Gravitational waves are disturbances in space-time，the very fabric of the universe，that travel at the speed of light．The waves are sent out by any mass that is changing speed or direction．The simplest example is a binary （二元的） system，where a pair of stars or compact objects （like black holes） orbit their common center of mass．
We can think of gravitational effects as curvatures （曲率） in space-time．Earth's gravity is constant and produces a static curve in space-time．A gravitational wave is a curvature that moves through space-time much like a water wave moves across the surface of a lake．It is generated only when masses are speeding up，slowing down or changing direction．
The new discovery was made by a group of more than 1，000scientists from universities around the United States as well as in 14other countries．Director David Reitze announced on Thursday at a press conference that they detected gravitational waves．
While opening a door to new ways to observe the universe，scientists said gravitational waves should help them gain knowledge about mysterious objects like black holes and neutron stars．The waves also may provide insight into the mysterious nature of the very early universe．
The scientists said that because gravitational waves are so radically （彻底地） different from electromagnetic waves they expect them to reveal big surprises about the universe．
21．Discovering gravitational waves would be a huge deal forC．
A．medicine．
B．literature．
C．cosmology．
D．philosophy．
22．The author explains the term of gravitational wavesD．
A．by classifying
B．by giving cause and effect
C．by making a comparison
D．by presenting a definition
23．The number of the countries that have scientists in the new discovery of gravitational waves isD．
A.12．
B.13．
C.14．
D.15．
24．What can be inferred from the last paragraph？A
A．Scientists can get further information about the universe by studying gravitational waves．
B．Scientists expect gravitational waves to reveal big surprises about the universe．
C．Gravitational waves are so radically different from electromagnetic waves．
D．Scientists from all the world work together to study the mystery of the solar system．
分析 科学家最近有了新发现，即引力波，并介绍了引力波的概念以及对于整个宇宙研究的重要作用．
解答 21-24CDDA
21．C 细节题．根据第二段开头Discovering gravitational waves would be a huge deal for physics，cosmology可知，引力波的发现对于物理学以及宇宙学来说是一次巨大的事情，故选C．
22．D 细节题．从第三段的内容介绍可知，Gravitational waves are disturbances in space-time，the very fabric of the universe…作者主要告诉我们什么是引力波，即用定义的方法来呈现，故选D．
23．D 推理题．文章The new discovery was made by a group of more than 1，000scientists from universities around the United States as well as in 14other countries这句话提到引力波的发现除了美国还有其他14个国家，所以一共是15个国家，故选D．
24．A 推理题．根据最后一句话The scientists said that because gravitational waves are so radically （彻底地） different from electromagnetic waves they expect them to reveal big surprises about the universe．
得知，科学家期望通过引力波的研究能揭示关于宇宙更多的奥秘，故选A．
点评 要想做好科普英语阅读理解题，同学们就要注意平时多读科普知识类文章，学习科普知识，积累常见的科普词汇，从根本上提高科普英语的阅读能力．
