How the Grand Canyon (大峽谷) was created remains one of the geology’s greatest mysteries. Some evidence suggests that the process was a gradual one in which the Colorado River (which runs through the canyon) slowly cut deeper and deeper into the ground over millions of years. But volcanic rock samples taken from the canyon now suggest that the canyon was down-cut instead.

Down-cutting is when a flood of water rushes over a landscape (地形) with enough force to cut deeply into the ground and leaves behind a canyon. Such a flood is usually released when a natural or man-made dam (堤壩) bursts.

Robert Webb, a research geologist, says natural dams seem to have formed and broken across the Colorado River several times during the last million years. The dams were built when lava(熔巖) from the eruptions of nearby volcanoes flowed into the river. The lava hardened into hard rocks and blocked the river, causing it to back up and form a lake. Each time the lake grew so huge that it broke the rock dam, releasing a flash flood that furthered the down-cutting process and deepened the canyon.

Down-cutting is not just an earthly event. Satellite photos sent back from Mars suggest that the process has happened there, too, say many other researchers.

The photos, taken by the Mars Global Surveyor, indicate that an enormous lake existed on Mars 3.5 billion years ago. The lake spilled into a large nearby hole. One edge of the hole broke, releasing a flash flood that quickly carved out a grand canyon.

The existence of down-cutting on Mars is just one more piece of evidence that the cold, dry planet was once warm and wet.

1.In the past, deep canyons were believed to have formed _______.

A. as a result of a sudden break of volcanoes

B. due to river flows over millions of years

C. owing to the burst of artificial dams

D. thanks to our ancestors’ creative work

2.According to the passage, which of the following statements is TURE?

A. Several volcanoes broke out on Mars directly creating grand canyons.

B. Several great lakes existed on the upper parts of the Colorado River.

C. People built high dams on the upper parts of the Colorado River.

D. The Colorado River crossed the Grand Canyon to form down-cutting.

3.From the last three paragraphs we learn that _______.

A. there are great lakes on Mars

B. there are active volcanoes on Mars

C. there might be cities on Mars

D. there might be life on Mars

4.The passage can be titled as _______.

A. Lakes on Earth and Mars

B. The Cause of Lake Formation

C. The Force of Dam Breaking

D. Canyons—Results of Flood Cutting

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Life comes in a package. This package includes happiness and sorrow, failure and success, hope and despair. Life is a learning process. Experiences in life teach us new lessons and make us a better person. With each passing day we learn to handle various situations.

Love

Love plays a vital role in our life. Love makes you feel wanted. Without love a person could become cruel and ferocious(殘忍的). In the early stage of our life, our parents are the ones who show us with unconditional love and care, and they teach us about what is right and wrong, good and bad. But we always tend to take this for granted. It is only after marriage and having kids that a person understands and becomes sensitive to others’ feelings. Kids make a person responsible and mature and help us to understand life better.

Happiness and Sorrow

Materialistic happiness is short-lived, but happiness achieved by bringing a smile on others’ face gives a certain level of fulfillment. Peace of mind is the main link to happiness. No mind is happy without peace. We realize the true worth of happiness when we are in sorrow. Sorrow is basically due to death of a loved one, failure and despair. But these things are temporary and pass away.

Failure and Success

Failure is the path to success. It helps us touch the sky, teaches us to survive and shows us a specific way. Success brings in money, fame, pride and self-respect. Here it becomes very important to keep our head on our shoulder. The only way to show our gratitude to God for bestowing(授予) success on us is by being humble, modest, courteous and respectful to the less fortunate ones.

Hope and Despair

Hope is what keeps life going. Parents always hope their children will do well. Hope makes us dream. Hope builds in patience. Life teaches us not to despair even in the darkest hour, because after every night there is a day. Nothing remains the same. We have only one choice: keep moving on in life and be hopeful.

Life teaches us not to regret over yesterday, for it has passed and is beyond our control. Tomorrow is unknown, for it could either be bright or dull. The only alternative is to work hard today, so that we will enjoy a better tomorrow.

1.What would be the best title for the passage?

A. Life is a Journey of Ups and Downs

B. Love Plays an Important Role in Our Life

C. Failure is the Path to Success

D. Hope Keeps Life Going

2.What is the author’s understanding of happiness?

A. Materialistic happiness leads to people living a short life.

B. Smiling to others adds to our happiness.

C. Happiness is temporary and passes away.

D. Happiness is closely related with peace of mind.

3.In the author’s opinion, tomorrow ________.

A. is beyond our control

B. is bright and hopeful

C. calls for today’s efforts

D. count for more than yesterday

4.The passage is most likely to be found in a ________.

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