题目内容
The author regards the idea that differentiation is triggered randomly when paired claws remain intact as ______ .
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SECTION B INTERVIEW
Directions: In this section you will hear everything ONCE ONLY. Listen carefully and then answer the questions that follow. Questions 1 to 5 are based on an interview. At the end of the interview you will be given 10 seconds to answer each of the following five questions.
Now listen to the interview.
听力原文：Mr. Jones: What materials were used for road surfaces during the last century？
Engineer: Usually they were gravel and macadam. Tars and asphalt were originally used only as coverings, but later they were used as binders and finally as hot mixtures.
Mr. Jones: Concrete is a modern material as far as road - building goes, isn't it？
Engineer: Relatively speaking. But you might be surprised to know that a concrete road was built as early as 1893 in Ohio. But it was only 5 miles long. More extensive projects were not undertaken until much later, around 1912 or 1913.
Mr. Jones: This was because of the increase in traffic？
Engineer: That's right. Especially in the use of heavy tracks. More rigid pavements, such as concrete and brick, became a necessity. For light traffic, though, water-bound macadam, gravel, sand clay, and bituminous mixtures were still used.
Mr. Jones: What are turnpikes usually made of？
Engineer: Turnpikes are usually made of reinforced concrete about 8 to 10 inches thick, placed on a granular sub-base, which in turn is placed on a well - tacked earth subgrade. Of course, the construction depends a lot on the local climate, rainfall, soils, and so on.
Mr. Jones: How do you mean--climate？
Engineer: Frost is one of the main problems. For example, in Maine, where frost is quite frequent, the typical turnpike construction is a thin top layer of asphaltic concrete on a base layer of sand and gravel placed on a 36 - inch, frost - free, granular sub - grade.
Mr. Jones: What is the width of these roads？
Engineer: The early two - lane roads were about 20 feet wide. But with higher automobile speeds, the width requirements increased greatly. To give you an example, the Pennsylvania Turnpike has two 12 - foot lanes in each direction, separated by a median 10 feet wide. On each side there is a 10 - foot stabilized shoulder, marking a total width of 78 feet. The New Jersey Turnpike averages 100 feet in width, with three lanes in each direction.
Mr. Jones: I guess wider roads are being built every day.
Engrneer: That's right. Sometimes you think that, no matter how good a road you build, the speed and weight of vehicles will always be one step ahead.
What materials were not used for road surfaces during the last century？
听力原文： Once again, US network television finds itself turning society's worst nightmares into a night of entertainment "you'll never forget."
The season finale of top - rated prime - time drama "ER" last week centred on the show' s doctors and nurses struggling to save several bloodied young gunshot victims after an angry father goes on a rampage at a foster care facility.
A night earlier, "Law & Order" drew the highest ratings of it 11 -year history with a ripped-from-the-leadlines episode about a high school cafeteria shooting and the trial of the teenage gunman, with faux home video footage of the killings.
And this Monday, a third NBC drama, "Third watch," wrapped its second season with police and paramedics rushing to the scene of yet another fictional high school massacre.
Media experts chalk it all up to the fierce rivalry of the current ratings "sweeps," combined with TV dramas' growing tendency to transform. news into fiction and the recent spate of real-life school violence making headlines.
For action and pathos, it is hard to beat the "ER', scene of emergency physicians scurrying to resuscitate a young girl lying limp on a hospital gallery, with sheets soaked in blood from a gunshot wound to her head, before they finally, somberly, declare her death and snap off their rubber gloves.
"It's gripping and it's disturbing," "Robert Universiy's centre for the study of popular television, said. Television is kind of the way that the entire collective subconscious of our culture plays out these issues".
Joseph Turow, a communications professor at the University of Pennsylvania and author of several books on the mass media, said the line between reality and fiction has be- come increasingly blurred on network TV.
"Viewers see multiple versions of the same reality, first on news programmes, then on so-called news magazines and then on entertainment shows like ER' and Law & Order," he said. "Some studies suggest that after a while, people won't be able to tell where they've gotten their information from."
Dramatic TV portrayal of children as victims of violence, neglect and abuse is nothing new. A famous episode of "Dragnet" in the 1960s depicted a couple who allowed their young child to drown in a bathtub while they were smoking pot.
It has been nearly 20 years since the real-life abduction and murder of Florida boy Adamwalsh was dramatized on the NBC TV movie "Adam," helping to publicize a case that turned the issue of missing children into a national crisis.
Now, the horror of kids being gunned down in schools and day care centers is on the public's mind, the latest grist for networks trying to grab viewers with “unforgettable” episodes of their favorite shows. "We're a show that has a long history of looking at the criminal justice system as it occurs," said Barry Schindel, executive producer and head writer of "Law & Order." "If we didn't do the show, people would be asking, why aren't your characters considering the events of a school shooting？"
The timing is hardly coincidence. Schindel said a flurry of school violence in southern California and elsewhere in early March caught the attention of "Law & Order" writes-- and probably those on other shows--at about the time they were brain storming ideas for the end of the current season.
Which programme is season finale top-rated prime-time drama？
SECTION C NEWS BROADCAST
Directions: In this section you will hear everything ONCE ONLY. Listen carefully and then answer the questions that follow. At the end of each news item, you will be given 10 seconds to answer the questions.
听力原文： At least 11 people died yesterday when a train struck a bus on a level crossing in Russia's Baltic enclave of Kaliningrad, the Interfax news agency reported.
Anatoly Klimov, deputy head of the local transport police, said an initial investigation indicated the bus went past a stop sign at the level crossing and was hit by an oncoming train.
Nine bus passangers were killed in the Collision, near the village of Ovrazhroye in the Kaliningrad region. Two more later died from their injuries and 17 were being treated in hospital. It was unclear whether the driver was among the victims.
"It is difficult to give the precise number of victims because there are a lot of body parts at the scene, and their identification will be difficult," Klimov said.
How did this accident happen？
Which of the following experimental results, if observed, would most clearly contradict the findings of Victor Emmer？
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