----- How on earth did these problems _______...

----- How on earth did these problems _______?

----- Because they ignored the advice of the expert．

A．come across                                    B．come down

C．come on                                        D．come about

高三英语单项填空中等难度题查看答案及解析

How much rain has fallen on the earth in the past? Man has not always kept weather records. Because scientists need a way to learn about past rainfall, they study the tree rings.

A tree’s trunk (树干) keeps growing year by year. Under its bark (树皮), a tree adds a layer of new wood each year it lives. If you look at a tree stump, you can see the layers. They are called annual ring (年轮).

On some trees, all of the rings are of the same width. But the ponderosa(美国黄松) that grows in the American southwest have rings in different withes. The soil in he southwest is dry. The pines depend on rainfall for water. In a year of good rainfall, they form wide rings. In a dry year, they form narrow ones.

Scientists do not have to cut down a pine to study its rings. With a special tool, they remove a narrow piece of wood from the trunk without harming the tree. Then they look at the width of each ring to see how much rain fell in the year it formed.

Some pines are hundreds of years old and have hundreds of rings. These rings are from an annual record o0f past rainfall in the southwest.

1.We could infer from the passage that ______.

2.A tree grows a new layer of wood _____.

3.On the whole, the passage is about _____.

4.The scientists _____ to know how much rain fell in a certain area in the past.

5.Which of he following is true according to the passage?

高三英语阅读理解中等难度题查看答案及解析

The bristlecone pine is the longest-living thing on the earth. These trees, with their strangely-shaped, wind-beaten limbs(枝干), can live up to 5,000 years. But experts worry that a warming climate in some areas may threaten its future.

Researchers say warmer weather is permitting a similar kind of tree, the limber pine, to take over good growing places from the ancient bristlecone. They say the tree is being crowded out of mountainous areas where it grows.

“The bristlecone pine is the oldest individually growing organism,” researchers say. They grow in high mountain forests in eastern California, Nevada and Utah. In those mountains, the trees face high winds and extreme temperatures, which leave them with twisted limbs and shapes. “Even in such tough conditions,” Brian Smithers, a researcher at the University of California, said, “the limber pine is taking all the good spots.”

The limber pine is the bristlecone’s distant relative and competitor. It can also live a long time——up to 2,000 years. And it is usually found at lower altitudes, where temperatures are warmer. However, according to a three-year study which centered on trees that have started growing in the last 50 years in California’s White Mountains, most of the trees growing at higher altitudes were limber pines.

Scientists compared the competing species to two o1d men in a very slow race up a mountainside. This race between such slow-growing trees takes thousands of years. They say climate change is causing the competition.

Smithers said the bristlecone pines are not in danger of disappearing. But he assumes they could be crowded out of some places where they have grown for thousands of years.

The researchers say the findings show how climate change can affect the two kinds of trees. The information, they say, can help scientists understand more complex forests.

1.What’s the function of Paragraph 1?

A. To introduce a topic.　　 B. To summarize the whole passage.

C. To describe the appearance of a tree.　　 D. To praise the hard work of the experts.

2.What does the underlined sentence in Paragraph 2 mean?

A. There will be older trees sent out of those mountains.

B. There will be more places covered with bristlecone pines.

C. There will be better limber pines replacing the ancient ones.

D. There will be fewer bristlecone pines growing in those areas.

3.According to the passage, the reason why limber pines can grow at higher altitudes is_________.

A. the high winds　　 B. the difficult conditions

C. the changing climate　　 D. the extreme temperatures

4.What is the researchers’ attitude towards the future of the bristlecone pine?

A. Positive.　　 B. Concerned.

C. Enthusiastic.　　 D. Indifferent.

高三英语阅读理解中等难度题查看答案及解析

_______ on earth is it _______ has eaten up all the leaves of these young trees in just

one night?

高三英语单项填空中等难度题查看答案及解析

---Where on earth did you get the book?

---_________

A. What did you say?　　　　 B. I beg your pardon?

C. Say it again!　　　　　　　　　 D. I didn’t get it on earth.

高三英语单项填空中等难度题查看答案及解析

—Where on earth did you get the book?

— ______

高三英语单项填空中等难度题查看答案及解析

—Oh, dear! I can’t find my new bracelet. Where on earth did I put it?

—What a careless guy. It is on the table______ we had dinner together yesterday.

A．which            B．that              C．where            D．what

高三英语单项填空中等难度题查看答案及解析

—Dad, where on earth did you put my raincoat?

—Oh, Jim．I forgot to tell you．It _________ behind your bedroom door．

A．would hang　　　 B．has hung

C．is hanging　　　　 D．hung

高三英语单项填空简单题查看答案及解析

I don't want to _______ the topic, but why on earth did you get home that late last night?

A. take up             B. make up          C. break up            D. bring up

高三英语单项填空中等难度题查看答案及解析

— Can you post these letters for us on your way home?

— ____.

高三英语单项填空简单题查看答案及解析