Question

    Death valley (死亡谷) is famous for its moving rocks. Since the early 1900s, visitors to Racetrack Playa, a dry lake bed in California have wondered how the rocks can move on their own.

These rocks leave long tracks (轨迹) behind them. The long tracks show that the rocks have moved along the ground. Those rocks only move at night and only move once every year or two. And they don’t move at the same time or in the same direction. But how do they move? How can a 350-kilogram rock move? Now scientists have known the key to the question!

Here’s how it happens.

Death Valley is one of the hottest places in the world, but it is cold at night. When it rains, the hard ground becomes soft and wet. When it gets cold enough, the water on the ground will change into very thin ice. Then the strong wind can move flat (平的) rocks along the flat ground In the morning, the sun comes up and dries the ground.

Moving rocks can be found at other places in the world as well, but Death Valley is the most famous.

1.What interests the visitors most in Death Valley?

A.The mountains around Death valley. B.The scenery of Death Valley.

C.The reason why the lake is dry. D.The secret of the moving rocks.

2.What shows the rocks can move?

A.The dry lake bed. B.The long tracks behind them.

C.The weight of the rocks. D.The shapes of the rocks.

3.How is the weather in Death Valley?

A.Hot in the day and wet at night. B.Cool in the day and dry at night.

C.Hot in the day and cold at night. D.Cold in the day and windy at night.

4.What can carry the rocks over the lake bed?

A.The wind. B.The heat. C.The rain. D.The visitors.

5.What’s the best title for this passage?

A.Dry Lake Bed B.Soft and Wet Ground

C.Tracks of Rocks D.Moving Rocks in Death Valley

Answer

1.D

2.B

3.C

4.A

5.D

【解析】

本文是一篇说明文。介绍了发生在死亡谷中的一个奇怪现象——石头会自己移动。文章通过分析死亡谷的地理特点，解开了“移动的石头”之谜。

1.细节理解题。根据短文第一段第二句“…a dry lake bed in California have wondered how the rocks can move on their own.”可知，死亡谷中会移动的石头最能吸引游客的兴趣。故选D。

2.细节理解题。根据短文第二段第二句“The long tracks show that the rocks have moved along the ground.”可知，石头后面留下的长长的轨迹证明了石头在移动。故选B。

3.细节理解题。根据第四段第一句“Death Valley is one of the hottest places in the world, but it is cold at night.”可知，在死亡谷中，白天炎热，夜间寒冷。故选C。

4.细节理解题。根据第四段第四句“Then the strong wind can move flat (平的) rocks along the flat ground.”可知，大风会吹着死亡谷中的石头移动。故选A。

5.主旨大意题。文章以会移动的石头为核心寻找这一秘密的答案，通过分析死亡谷的地理特点，破解了人们多年的谜团。故选D。