已知函数f(x)=x2+bx+c,(b,c∈R),集合A = {x丨f(x)=0}, B = {x|f(f(x)))= 0},若存在x0∈B,x0A则实数b的取值范围是 A B b<0或 C D 答案:C 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.
Grirmsvom is one of
the largest and most active volcanoes in Europe. What makes Grimsvom different
is that it lies under a huge glacier(冰川) of ice up to 12 maters 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 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, causing damage to the
plane.
The
eruption has also caused problems for animals in Iceland. The volcano left ash
and sharp. Glass-like rocks all over the countryside. Farmers are keeping their
animals inside to stop them from eating ash- covered grass to the sharp
object.
1.What keeps Grimsvom
still?
A. The
slow flow of water B. The low water
temperature
C. The
thick glacier
D. The water pressure
2.Which of the
following is true?
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
3. This text is most
probably taken from_______________.
A. a
research
paper B. a
newspaper report
C. a class
presentation D. a
geography textbook.