[单项选择]A A volcanic eruption in Iceland has sent ash across northern Europe.Airlines have stopped or changed the flights across the Atlantic Ocean,leaving hundreds of passengers stuck in airports. Grimsvotn is one of the largest active volcanoes in Europe.What makes Grimsvotn different is that it lies under a huge glacier（冰川） of ice up to 12 meters thick.The hot volcano heats up the ice above it,which then forms a layer（层） of water between the glacier and the volcano.This layer of water puts pressure on the volcano,keeping it stable.As the water flows out from under the glacier,the pressure lifts.The lava（岩浆） from the volcano then comes up to the surface.This is exactly what has happened today. Now,airlines have to make changes to their flights so as not to fly through the clouds of volcanic ash.According to KLM,one of Europes biggest airlines,airplanes cannot go under the cloud or over it.Going through the cloud can result in ash getting stuck in the airplanes engines,caus
A. People stop traveling in Europe.
B. Airlines suffer from the loss of planes.
C. It becomes dangerous for animals to eat outside.
D. Farmers have lost many of their animals.

[单项选择]A A volcanic eruption in Iceland has sent ash across northern Europe.Airlines have stopped or changed the flights across the Atlantic Ocean,leaving hundreds of passengers stuck in airports. Grimsvotn is one of the largest active volcanoes in Europe.What makes Grimsvotn different is that it lies under a huge glacier（冰川） of ice up to 12 meters thick.The hot volcano heats up the ice above it,which then forms a layer（层） of water between the glacier and the volcano.This layer of water puts pressure on the volcano,keeping it stable.As the water flows out from under the glacier,the pressure lifts.The lava（岩浆） from the volcano then comes up to the surface.This is exactly what has happened today. Now,airlines have to make changes to their flights so as not to fly through the clouds of volcanic ash.According to KLM,one of Europes biggest airlines,airplanes cannot go under the cloud or over it.Going through the cloud can result in ash getting stuck in the airplanes engines,caus
A. It is below ice.
B. It lies under the sea.
C. It is the largest volcano.
D. Its lava affects the airlines.

[判断题]The volcanic eruption affected hundreds of miles across in Philippines.

[判断题]

The second-largest volcanic eruption of the 20th century, and by far the largest eruption to affect a densely populated area, occurred at Mount Pinatubo in Philippines on June 15, 1991. The eruption produced high-speed massive falling of hot ash and gas, giant mudflows, and a cloud of volcanic ash hundreds of miles across. The impacts of the eruption continue to this day.
A huge cloud of volcanic ash and gas rose above Mount Pinatubo, Philippines, on June 12,1991. Three days later, the volcano exploded in the second-largest volcanic eruption on Earth in this century. Timely forecasts of this eruption by scientists from the Philippine Institute of Volcanology and Seismology and the US Geological Survey enabled people living near the volcano to evacuate to safer distances, saving at least 5000 lives.
On July 16,1990,a magnitude 7. 8 earthquake (comparable in size to the great 1906 San Francisco, California, earthquake) struck about 60 miles (100 kilometers) northeas

[单项选择]

W: The volcanic ash from the eruption of Mount Saint Helens certainly caused a lot of damage, didn’t it
M: It did, but not as much as experts have predicted. It seems to have had a beneficial effect as well.
W: Really But were crop losses great
M: Yes, However, since the weather following the eruption was unexpectedly good, some crop yields remained steady or even increased beyond normal expectancy levels.
W: I’m glad to hear that. But what was the beneficial effect you mentioned
M: A mass destruction of various insect populations.
W: How could the ash kill insects without effecting people too
M: It’s highly abrasive and quickly wears away the outer wax layer, protecting insects bodies. Removal of that layer causes the insects to lose body moisture by evaporation, the result is usually lethal.
W: How about that Sounds like an effective yet natural insecticide.

What is the main topic of the conv
A. The conversion of volcanic waste to fertilizer.
B. The menace of currently dormant volcanoes around Mount Saint Helens.
C. The eruption of Mount Saint Helens and its effects on the environment.