题目内容：

    We humans are a curious species． As NASA says on its website，"Humans are driven to explore the unknown， discover new worlds， push the boundaries of our scientific and technical limits，and then push further． "

And space exploration is where we\e been "pushing" our furthest curiosity．

The year 2019 began with two pieces of exciting space exploration news． On Jan． 3， China landed a spacecraft，Chang′e 4，on the moon's far side﹣the side we can′t see from Earth﹣for the first time in human history． And according to a report published on Jan． 9 in Nature， scientists from the Canadian Hydrogen Intensity Mapping Experiment （CHIME） detected repeated radio signals from a galaxy 1.5 billion light years away， possibly sent by intelligent aliens．

However， what，s even more exciting than the news is the fact that whenever speaking of space exploration， we forget our political and cultural differences﹣the things that so obsess us．

"When you go into space， you become part of this overall collective （集体）called ‘humanity， Ken Liu， Chinese﹣American sci﹣fi writer and translator，told Quartz website． "You′re no longer Chinese， American， Russian …Your culture is left behind． You're now just ‘humanity' with a capital ‘H'． "

This magic has worked all the way along our journey into space． When US astronaut Neil Armstrong （1930﹣2012）became the first human to set foot on the moon in 1969， for example，he told the world： "That's one small step for man， one giant leap for mankind， "Now， with Chang'e 4 touching down on new moon territory， China′s aim is to help scientists from around the world find out more about Earth's only satellite． And with the discovery of the CHIME astronomers， we ' re one step closer to answering a common question in science： "Are humans alone in the universe？"

It's true that we are a curious species． But instead of being curious about the "unknown"， perhaps we're really more eager to "push further" our own human "boundaries" and "limits"．

1.Which of the following is the discovery of the CHIME scientists？

A. A galaxy with intelligent aliens．

B. Repeated radio signals sent by intelligent aliens．

C. Repeated radio signals from a distant galaxy．

D. Radio signals from a galaxy several years ago．

2.Why does the author quote Ken Liu's words ？

A. To introduce the famous writer， Ken Liu．

B. To show that in space we are just humanity．

C. To emphasize that culture is not important．

D. To introduce the things that obsess us very much．

3.What does the author intend to do in paragraph 6？

A. Further confirm his opinion．

B. Add some background information．

C. Summarize the previous paragraphs．

D. Introduce a new topic for discussion．

4.What's the main idea of the text？

A. China takes the lead in space exploration．

B. Humans are not alone in the universe．

C. Space exploration is a common cause of mankind，

D. Humans desire to push the boundaries of scientific limits．