LONDON: What could possibly be wrong with pla...

LONDON: What could possibly be wrong with planting trees? The benefits are obvious; they  firm the soil, soak up (摄取) extra water and take carbon dioxide (二氧化碳) out of the atmosphere.

However, it now turns out that planting trees could add to global warming.

Tree roots do a great job of keeping soil firmly on the ground and out of the wind’s power. The problem is that some of those dust clouds play an important part in taking in carbon dioxide.

Huge dust storms blow out over the oceans from dry parts of North Africa and central Asia. Tons of dust are lifted and left as a thin film over the ocean surface. The dust fuels oceanic life.

Dust from China is carried east and left in the Pacific Ocean. If a tree-planting programme there is successful and the dust supply reduced, the final result may be that less carbon dioxide gets locked away in the ocean.

Andy Ridgwell, an environmental scientist from the University of East Anglia, has spent the past few years studying dust and says his work “shows clearly the complexity of the system and the importance of not tinkering(粗劣地修补) with it without understanding the results. For this reason the need is to focus(集中) on cutting carbon dioxide giving off rather than monkeying (瞎弄) about with the land surface.”

An American scientist, Robert Jackson, has shown that when native grassland areas are invaded(侵入) by trees, carbon is lost from the soil. “We are studying why the soil carbon disappears, but one theory is that trees do a lot more of their growing above ground compared to grasses, so less carbon goes directly into the soil from trees, ” says Jackson.

In wet areas of the world, the gain from trees absorbing carbon dioxide above ground seems to be outweighed(超过) by the loss of carbon from the soil below ground. Countries that plan to combat global warming by planting trees may have to think again.

Solutions to environmental problems are often more complex than they first appear, and understanding the Earth’s climate is a very great challenge.

1.People usually hold the opinion that_____________.

A. huge dust storms can destroy carbon dioxide

B. huge dust storms can destroy the oceans on the earth

C. huge dust storms can’t do anything beneficial for man

D. planting trees is the only way to control huge dust storms

2. Andy Ridgwell, the environmental scientist, believes that_____________.

A. dust plays a more important part than trees

B. trees shouldn’t have been planted in dry places

C. carbon dioxide is harmful to everything on the earth

D. environmental problems are more complex than expected

3. Robert Jackson’s experiment proves that_____________.

A. grassland areas should be covered by forests

B. trees hold more carbon than grasses

C. carbon can turn grass into dust

D. less carbon can make trees grow faster

高三英语阅读理解中等难度题查看答案及解析

—Could you help me with the math problem?

—________ Your must be barking up the wrong tree.

A．A pleasure.　     B．Hang on a minute.

C．What’s the point?　     D．Are you kidding?

高三英语单项填空中等难度题查看答案及解析

Now that the forest was destroyed by a big fire, a large ________of trees ______ to be planted on the mountain．

高三英语单项填空简单题查看答案及解析

—Look! More trees are being planted around the new building. What do you think of ________natural surroundings here?

—Fantastic! Beyond _______ expression.

A. the; 不填       B. the; the    C. 不填; 不填       D. the ; an

高三英语单项填空困难题查看答案及解析

Something ________ wrong with the car, and it ________ not start.

高三英语单项填空中等难度题查看答案及解析

Scientists have found what look like caves on Mars(火星),and say they could be protecting life from the planet’s terrible environment.

Images of the Mars caves from Northern

Arizona University

The first caves discovered beyond the Earth appear as seven mysterious black dots on the pictures sent back by NASA’s Mars Odyssey orbiter.Each as large as a football field,they may be openings into natural caves below the Martian surface.

“If there is life on Mars,there is a good chance you’d find it in caves,”said Jut Wynne,one of the researchers who noticed the features while working on a US Geological Survey Mars Cave Detection Program.

Jonathan Clarke,a geologist with the Mars Society of Australia,yesterday described the discovery as exciting.

One photo taken at night by an infrared imager(红外线成像器) showed one hole to be unusually warm,suggesting hot air trapped during the day is flowing out.

“I said:‘Wow,that’s a cave’,”Dr.Clarke said excitedly.“People have been looking for these for a long time;now we have found them.”

He agreed such caves would be perfect places to hunt for life escaping from the bitterly cold,radiation-soaked(充满辐射的),dry surface.

“Tiny drops of water could collect inside,”he said.“If there are gases coming out,they could provide energy for a whole range of bacteria.A cave is also a protection from radiation;the surface of Mars is exposed to high levels of space radiation.”

The caves probably formed when tube-shaped lava flows(管状岩浆流) spread across the planet long ago.The outside of the tubes cooled,forming solid walls,while something hotter inside allowed the remaining lava to flow out,forming caves.

1.What does the passage mainly talk about?

A.How the caves were formed on Mars.

B.How scientists found these caves on Mars.

C.Caves on Mars may be full of hot air or a sign of life.

D.Scientists have completely recognized the surface of Mars.

2.We can learn from the passage that _______.

A.water has already been found on Mars

B.the scientists found all the caves at night

C.it is certain that there is life in these caves

D.the surface of Mars is bitterly cold,radiation-soaked and dry

3.According to the passage,Dr.Clarke was so excited because _______.

A.such caves could provide energy for life

B.they had finally found the caves on Mars

C.such caves would be perfect places to hunt for life

D.scientists had long been looking for these caves

4.Necessary conditions for life on Mars mentioned in the passage may include _______.

A.lava and energy

B.water and radiation from space

C.gases and lava

D.water and protection from radiation

高三英语阅读理解中等难度题查看答案及解析

What’s wrong with the radio?

A. It can’t be turned on.　　 B. It can’t be turned off.　　 C. It doesn’t work.

高三英语短对话简单题查看答案及解析

It could be learned from the teacher's eyes ________ he was very satisfied with her performance.

A．that     B．whether

C．what     D．where

高三英语单项填空中等难度题查看答案及解析

In spring, you may have seen white foam(泡沫) on a green tree or other plants. As a matter of fact, the foam is where young spittlebugs(吹沫虫) live. These insects are protected by the foam, and they usually don’t do much harm to the plants.

As we all know, in late summer, a mother spittlebug lays her eggs on the plant. The babies will hatch(孵化) in spring. After they come to the new world, they begin to eat juice from the plant. The babies eat more juice than their bodies need for food. The extra juice mixes with a special waste that the spittlebugs produce. When this fluid(液体) is released, it mixes with the air, forming bubbly foam.

What is so great about having a foam home? The space inside is so wet that it can keep the bugs’ soft bodies from drying out. And the foam tastes bad, so it keeps away most animals that would eat the bugs. Some birds will reach their heads through the foam to find the bugs. Wasps and ants might eat them, too. But most of the bugs stay safe inside the foam.

Once the bugs have grown into adults, they stop making foam. They leave their homes and jump from plant to plant in search of food. The adults look a little like tiny frogs. For this reason they are also called froghoppers.

If you see some foam on a plant, you might want to take a careful look inside. Gently push some of the foam aside with a small stick. Deep inside you may see a few insects eating plant juice. They might also be making more foam. Be sure to push the foam back after a moment to cover the insects and keep them safe. Soon the spittlebugs will grow up and leave their foam home. They will join the other insects in the grassland.

1.The eggs of spittlebugs_____.

A. are laid in late spring

B. have to pull through a winter before they hatch

C. are protected by mother spittlebugs all the time

D. will be eaten by ants

2.According to the passage, the white foam_____.

A. does much harm to the plant

B. protects the plant from being harmed

C. is where a mother spittlebug is living

D. is plant juice mixed with spittlebugs’ waste and the air

3.Which of the following is a function of a foam home?

A. Protecting the bugs from being eaten.

B. Helping the bugs find food.

C. Providing enough drinking water for the bugs.

D. Keeping the plant from drying out.

4.After the spittlebugs grow into adults, they______.

A. continue to make foam

B. take on a different look

C. begin to eat tiny frogs

D. begin to do harm to plants

高三英语阅读理解中等难度题查看答案及解析

What a pity! I _____ in London for three more days, but something urgent needed to be dealt with back in Beijing.

高三英语单项填空简单题查看答案及解析