Geologists have been studying volcanoes for a long time.Though they have learned a great deal,they still have not discovered the cause of volcanic action.They know that the inside of the earth is very hot,but they are not sure exactly what causes the great heat.Some geologists have thought that the heat is caused by the great pressure of the earth's outer layers.Or the heat may be left from the time when the earth was formed.During the last sixty years scientists have learned about radium,uranium,thorium,and other radioactive elements.Many scientists now believe that much of the heat inside the earth is produced by radioactive elements. Whatever the cause of the heat may be,we do know that the earth gets hotter the farther down we dig.In deep mines and oil wells the temperatures rise about 1degF for every 50 feet.At this rate of the temperature 40 miles below the earth's surface should be over 4 000deg.This is much hotter than necessary to melt rock.However,the pressure of the rock above keeps most materials from melting at their usual melting points.Geologists believe that the rock deep in the earth may be plastic,or puttylike .In other words,the rock yields slowly to pressure but is not liquid.But if some change in the earth's crust releases the pressure,the rock melts.Then the hot,liquid rock can move up toward the surface. The cause for the great heat inside of the earth is _ . A) great pressure of the earth's outer layers B) the heat left from the time when the earth was formed C) radioactive elements giving out heat D) not sure
D
It seems like every year brings a new outbreak of sickness.Recent research tells us how diseases spread, from person to person.And it also gives us an idea how we can spread something better than diseases. An author called Malcom Gladwell recently published a book explaining how the process works.We usually think of an epidemic as a force of nature that rolls over anyone in its way.In fact, it starts with a single person or very few people.These people travel around and infect small groups in different places.When enough of these groups are infected, then the disease suddenly seems to be everywhere.Gladwell also found that the process of infection was not just limited to disease? It also affects the world of ideas. The process can be seen in books and fashion.So called _ are not pushed towards the public.They spread through hundreds of small reading groups until the day when everybody you know seems to have a copy.A group of young people may decide to wear an item of clothing simply because no one else is wearing it.Designers who monitor street fashion then pick up the idea and spread it.Finally everyone is wearing it. New York is often described as an unfriendly place.People are too busy looking after business to look after each other.In the early 1990s, one unknown person decided to perform at least one kind act a day.This caught on with his or her friends.The newspapers noticed the trend .New York became full of people smiling and carrying each other's bags. The success of trends like this fits in with other social phenomena .One is the 80/20 rule.This was invented by economists who noticed that in any situation 20 percent of the people did 80 percent of the work.Another is the "bystander problem".Psychologists noticed that in accidents where a large number of people were around, no one stepped forward to help.Each person supposed that someone else would do something.When there were less people present, more of them decided to offer help. What all this proves is... According to the passage, we know _ . A) The "epidemic model" doesn't exist nowadays. B) The "epidemic model" plays an important role in making a business grow or spreading an idea. C) The "epidemic model" came into being in the early 1990s. D) The "epidemic model" is a book written by Malcolm Gladwell.
B
Q: Listed here are four of the thousands of impressive museums around the world. The Guggenheim Museum Bilbao in Bilbao, Spain Built in 1997, the Guggenheim Museum Bilbao is one of the newest in the world. It has transformed the industrial city of Bilbao into a travelers' desired destination. The beautiful architecture of the museum has provided a dramatic background for movies and commercials. The Louvre in Paris, France Probably the most famous Louvre also holds the most famous painting in the world, the"Mona Lisa"by Leonardo da Vinci. Crowds can be found any day surrounding the small, but mysterious painting of the smiling woman. But, the Louvre is much more than a home to the"Mona Lisa". The Louvre is visited by more people each year than any other museum in the world. The Barnes Foundation in Philadelphia, America Just opened in its new downtown location in 2012, the Barnes Foundation is unique in that it is a completely reproduced display from one man's private collection. Dr. Albert C. Barnes started collecting art in the early 20th century and collected, among others, the largest number of original Renoir paintings in the world. The Uffizi Gallery in Florence, Italy Walking on the marbled floors feels like stepping back in time. The building itself is a beautiful palace-like structure with frescoes decorating the ceilings and walls. Viewers are bowled over by the works by Botticelli, such as"The Birth of Venus". Classic artworks from nearly 1,000 years ago describe religious events of the time. Which of the following is the most popular? A) The Louvre. B) The Guggenheim Museum Bilbao. C) The Barnes Foundation. D) The Uffizi Gallery.
A: A
(Q).
The National Park Service in the United States will mark its one hundredth anniversary in 2016. As it nears its second century, the Park Service plans to increase its educational programs for students and teachers. The plans include transportation support for one hundred thousand students each year to visit national parks to learn about nature and history. Yellowstone is believed to have been the world's first national park when it was established in 1872. Other students will get a chance to see parks in faraway places through Skype and other online programs. The National Park Service also works with partners to provide education. One of its partners is a nonprofit organization called NatureBridge. NatureBridge is celebrating its fortieth anniversary and says one million young people have taken part in its programs. The organization works with students from kindergarten through twelfth grade and uses national parks as its classrooms. It provides field science programs at Yosemite National Park and four other locations in California and the northwestern state of Washington. Now, NatureBridge is launching an East Coast center with a four-million-dollar grant from Google. The program will begin in April at the Prince William Forest Park in Virginia. Students stay for three to five days in NatureBridge programs. The activities are aimed at developing their science skills. For example, they learn about different soils and study water quality under a microscope. Jason Morris, executive vice president of NatureBridge says when they are not sleeping, eating or in a laboratory, the students spend their time outdoors. Julia Washburn is associate director of education and interpretation for the National Park Service. She says in a time of budget cuts, the agency has to find ways to still meet its goals. And one of the most important services that the Park Service provides every day is nature interpretation. According to the text, NatureBridge_. A) finances all the programs alone B) is aimed at laboratory activities C) has benefited quite a lot of students D) provides online field science programs
(A).
C