Question

Now a group of scientists, including ones from CalTech, MIT and the LIGO Scientific Collaboration finally found the gravitational waves(引力波)．They announced they were able to see ripples(波纹) in the structure of spacetime.

What are these gravitational waves? Well, imagine throwing a rock into a pond. When the rock hits the flat surface of the water, it creates ripples. Spacetime is like the surface of the water. So gravitational waves are like the ripples moving out from where the rock hits the water.

It was Einstein who said these gravitational waves should be observable. But these are not huge waves. They are smaller than the size of an atom, which is why it took so long to find them.

Since 2002, scientists have been watching for these gravitational waves, using a giant scientific tool called LIGO. They have been watching two black holes in another galaxy(星系) faraway. The two were spinning around each other, moving closer and closer together. When they finally crashed into each other, gravitational waves were caused. With great power and force, they rang throughout the universe, like a giant bell. Those waves, traveling at the speed of light, finally reached the Earth, some 1.3 billion years later. The National Science Foundation said that each of the black holes was 29 to 36 times the mass of our sun.

This discovery means our understanding of the heavens has changed greatly.

1.The author explains the gravitational waves by ________.

A. presenting recent research findings

B. drawing a vivid picture

C. comparing them to something familiar

D. using proper examples

2.According to the author, finding the gravitational waves means ________.

A. there is a better way to deal with physics problems

B. we have a better understanding of the universe

C. we have reached a new level in earth studies

D. there exists another galaxy in the universe

3.What does the word “they” in Paragraph 4 refer to?

A. The black holes.

B. The gravitational waves.

C. The scientific tools.

D. The galaxies.

4.This passage mainly talks about ________.

A. a new theory of gravitational waves opposite to Einstein’s

B. a description of the scientific research on black holes

C. the relationship between black holes and gravitational waves

D. the discovery of gravitational waves Einstein believed observable

Answer 1