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.

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Life Lessons

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Dear Bill:

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A Language Programme for Teenagers

Welcome to Teenagers Abroad! We invite you to join us on an amazing journey of language learning.

Our Courses

Regardless of your choice of course, you’ll develop your language ability both quickly and effectively. Our Standard Course guarantees a significant increase in your confidence in a foreign language, with focused teaching in all 4 skill areas—speaking, listening, reading and writing. Our Intensive Course builds on our Standard Course, with 10 additional lessons per week, guaranteeing the fastest possible language learning (see table below).

Course Type

Days

Number of Lesson

Course Timetable

Standard Course

Mon-Fri

20 lessons

9:00-12:30

Intensive Course

Mon-Fri

20 lessons

9:00-12:30

10 lessons

13:00-14:30

Evaluation

Students are placed into classes according to their current language skills. The majority of them take on online language test before starting their programme. However, if this is not available, students sit the exam on the first Monday of their course. Learning materials are provided to students throughout their course, and there will never be more than 15 participants in each class.

Arrivals and Transfer

Our programme offers the full package—students are taken good care of from the start through to the very end. They are collected from the airport upon arrival and brought to their accommodation in comfort. We require the student’s full details at least 4 weeks in advance.

Meals/Allergies(過敏)/Special Dietary Requirements

Students are provided with breakfast, dinner and either a cooked or packed lunch(which consists of a sandwich, a drink and a dessert). Snacks outside of mealtimes may be purchased by the student individually.

We ask that you let us know of any allergies or dietary requirements as well as information about any medicines you take. Depending on the type of allergies and/ or dietary requirements, an extra charge may be made for providing special food.

1.How does Intensive Course differ from Standard Course?

A. It is less effective.

B. It focuses on speaking.

C. It includes extra lessons.

D. It give you confidence

2.Before starting their programme, students are expected to ________.

A. take a language test

B. have an online interview

C. prepare learning materials

D. report their language levels

3.With the full package, the programme organizer is supposed to ________.

A. inform students of their full flight details

B. look after students throughout the programme

C. offer students free sightseeing trips

D. collect students’ luggage in advance

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