US researchers have found traces of an ancient lake on Mars recently, increasing hopes of discovering evidence that billions of years ago the Red planet hosted life.

    The lake, which dates back some 3.4 billion years, appears to have covered as much as 80 square miles and was up to 1,500 feet deep, said the team from the University of Colorado.

    “This is the first clear evidence of shorelines on the surface of Mars,”said Boulder’ s research associate, Gaetano Di Achille, in a study published in the latest edition of Geophysical Research Letters.

   “The identification of the shorelines and accompanying geological evidence allows us to calculate the size and volume of the lake, which appears to have formed about 3.4 billion years ago.”

   Analysis of the images has shown the water carved out the canyon (溪谷) in which it was found, which then opened out into a valley depositing (使淤積) sediment (沉積) which formed a delta (三角洲).

  “Finding shorelines is a great discovery to us,” said assistant professor Brian Hynek, adding it showed the lake existed at a time when Mars was thought to have been cold and dry.

    Scientists believe the oldest surfaces on Mars formed during the wet and warm era known as the Noachan epoch, about 4.1 billion to 3.7 billion years ago.

The newly discovered lake is believed to date from the Hesperian era and postdates the end of the warm and wet period on Mars by 300 million years, according to the study.

 Scientists believe deltas next to the lake may well hold secrets about past life on Mars as such places on Earth have become the natural deposits of organic carbon and other markers of life.

1.The size of the lake found on Mars is ______.

A. 80 square miles                  B. 1,500 square miles

C. 3.4 billion square miles             D. 300 million square miles

2.When the lake existed, the weather on Mars was ____.

A. hot and wet      B. wet and warm         C. cold and dry     D. cold and wet

3.Why do scientists think deltas near the lake may hold secrets about past life on Mars?

A. Because similar places on Earth have become natural deposits of markers of life.

B. Because someone has put secrets about past life on Mars there.

C. Because past life has been found in other deltas on Mars.

D. Because some people are said to have already seen life marks there.

4.Which of the following statements is NOT true according to the passage?

A. The Noachan epoch was a wet and warm era.

B. The lake might have existed 3.4 billion years.

C. The discovery can’ t fully prove that the Mars once hosted life.

D. The lake traces prove that there exists life on Mars now.

 

【答案】

 

1.A

2.C

3.A

4.D

【解析】略

 

練習(xí)冊(cè)系列答案
相關(guān)習(xí)題

科目:高中英語 來源: 題型:

一why not join us in the collective dancing?

 一       

A.Sure,please

B.I don’t like dancing

C.That’s all right   

D.OK,coming

查看答案和解析>>

科目:高中英語 來源: 題型:

The final examination is coming up soon. It’s time for us to ________ our studies.

A. get down to       B. get out

C. get back for       D. get over

查看答案和解析>>

科目:高中英語 來源: 題型:

To save class time, our teacher has ___ students do half of the exercises in class and complete the other half for our homework.

A. us       B. we

C. our     D. ours

查看答案和解析>>

科目:高中英語 來源: 題型:閱讀理解

The United States will introduce a new and comprehensive(綜合的) exam for students who seek to study in American and other English-speaking countries, Xinhua News Agency reported from New York.

The exam, which stands for a great change from the current English level test, was disclosed by Theresa Chang Wei Jen, associate director of the International Service of the US College Board, America’s leading educational organization.

The Advanced Placement International English Language (APIEL) will be offered for the first time throughout the world on May 10, 2002, said Jen.

However, the APIEL is a strange title to most Chinese students, and it is unlikely to soon gain the similarity of other already existing exams, such as the TOEFL(Test of English as a Foreign Language), the GRE(Graduate Record Examination), or the IELTS(International English Language Testing System).

“I have never heard of such a test and I would prefer the IELTS if I need another exam,” said Xu Jingyan, a graduating student from Beijing University of Aeronautics and Astronautics, who wants to study in England and has already taken the TOEFL.

Most of Xu’s classmates have never heard of the APIEL. “The APIEL is designed for international students who wish to get university studies in English-speaking countries, including the United States, Britain, Canada, and Australia.” said Jen.

The APIEL has been adopted, said Jen, because the TOEFL can no longer accurately reflect the abilities of students of using the English language comprehensively in an academic environment. Xinhua reported that a fairly large number of foreign students who earned high scores in TOEFL exam turned out to be very ordinary educational performers after admission.

Compared with the TOEFL, the APIEL measures a student’s ability to read, write, speak and understand English through testing his or her skills in listening comprehension, speaking with accuracy(精確) and resourcefulness, and writing with clarity and fluency(流暢), Jen said.

1. The United States will introduce a new exam because _______.

A. more and more students want to get further education in the USA

B. the Chinese people pay special attention to English studies with China’s entry into the WTO

C. the already existing exam systems seem to be far from perfect

D. it will bring the US government quite a lot of money

2. Which of the following statements is TRUE according to the selection?

A. It will take quite a period of time for people to accept the APIEL.

B. The TOEFL is more popular with the Chinese than the IELTS.

C. A student will have to take the APIEL if he or she wants to study in English—speaking countries from 2002.

D. Chinese students will prefer the IELTS rather than the APIEL even in the future.

3. The underlined word current in the second paragraph means _______.

A. modern            B. present             C. standard           D. formal

4. Please decide which of the following would be the best title for this news report.

A. The Key to English-speaking Countries

B. The Four Skills in Learning English

C. TOEFL, IELTS and GRE to be Out of Date

D. New Exam Designed for Students

查看答案和解析>>

科目:高中英語 來源: 題型:閱讀理解

CARDIFF, Wales Poets, singers and musicians from across the globe gathered in Wales to celebrate the tradition(傳統(tǒng)) of storytelling.

“It might seem strange that people still want to listen in age of watching television, but this is an unusual art form whose time has come again,” said David Ambrose, director of Beyond the Border, an international storytelling festival(節(jié)) in Wales.

    “Some of the tales, like those the Inuit from Canada, are thousands years old. So our storytellers have come from distant lands to connect us with the distance of time,” he said early this month.

Two Inuit women, both in their mid 60s, are among the few remaining who can do Kntadjait, or throat singing, which has few words and much sound. Their art is governed by the cold of their surroundings, forcing them to say little but listen attentively.

    Ambrose started the festival in 1993, after several years of working with those reviving (coming back into use or existence) storytelling in Wales.

    “It came out of a group of people who wanted to reconnect with traditions. and as all the Welsh are storytellers, it was in good hands here.” Ambrose said.

1. Ambrose believes that the art of storytelling _______.

A. will be more popular than TV

B. will be popular again

C. started in Wales

D. are in the hands of some old people

2. From the tales told by the Inuit, people can learn _______.

A. about their life as early as thousands of years ago

B. why they tell the stories in a throat-singing way

C. how cold it has been where the Inuit live

D. how difficult it is to understand the Inuit

3. According to the writer, which of the following is NOT true?

A. Storytelling once stopped in Wales.

B. Storytelling has a long history in Wales.

C. Storytelling is always well received in Wales.

D. Storytelling did not come back until 1993 in Wales.

4. The underlined phrase in good hands means _______.

A. controlled by rich people         B. grasped by good storytellers

C. taken good care of                   D. protected by kind people

查看答案和解析>>

同步練習(xí)冊(cè)答案