题目内容：

请认真阅读下列短文，从短文后各题所给的A、B、C、D四个选项中，选出最佳选项。

Amazingly, US crime figures have been falling for 20 years now．Of course, the big question is, why? And can any lessons be learnt?

One reason could be the fall in the demand for the drug crack．During the 1980s, drug-related crimes soared, mostly caused by desperate crack users．However, according to professor Blumstein, co-author of The Crime Drop in America, news of the dangers of crack use caused its decrease and led to a fall in the number of drug-related crimes.

Some say that the adoption of a zero-tolerance policy in many cities has helped lead to a fall in crime．In New York City, for example, mayor Rudy Giuliani imposed strict and automatic punishments for all crimes, including minor offences such as graffiti and littering．Many believe this has had a very strong deterrent(威慑的) effect.

Another reason could be smarter policing strategies．Anti-theft measures and educating the community about car theft has helped see a drop in crimes in many areas．Also, the use of crime mapping schemes that can discover identify crime peaks in different parts of the city has helped police target hotspots.

Another reason could be that more criminals are now behind bars．Sociologist John Conklin (from Tufts University) says a significant factor behind the fall in crime in the 1990s is the simple fact that many criminals are in jail．In his book Why Crime Rages Fell, he says sentencing was merciful in the 1960s and 1970s, when crime rose．But then more prisons were built and more offenders were imprisoned.

Some have linked the fall in violent crime to a decline in children’s exposure to lead in petrol．Jessica Wolpaw Reyes says, “Even low to moderate levels of exposure can lead to behavioral problems, reduced IQ, hyperactivity(多动症) and youth crimes．You can link the decline in lead between 1975 and 1985 to a decline in violent crime 20 years later.”

Others say that the drop in crime has something to do with birth rates．According to statistics, birth rates peaked between 1957 and 1961, and the proportion of men in the US in their late teens and early 20s (the so-called “criminal age”) was highest in the late 70s and early 80s．However, as time went on, the proportion of people in this age group decrease

Others claim that videogames have helpe

A recent study has suggested that these games are keeping young people off the streets and therefore away from crime．Advocates of this argue that any effects the games may have in encouraging violent behavior is offset by the fact that the games keep potential criminals indoors and in front of the television．

Some argue that the widespread use of camera phones makes some criminals think twice before committing a crime and getting filmed doing it．Also, many believe that the mass use of CCTV has also had an effect.

Finally, some say that petty theft just isn’t worth it any more．The resale value of second-hand goods such as televisions, cameras or clothes is now so low (or even non-existent) that most people see no point in stealing．

So, what do you think?

1.By writing this article, the writer intends to tell us _____.

A．the amazing fact that US crime figures are going down

B．the recent statistics showing that crime rates are falling in the US

C．the answers to the question why US crime figures are falling

D．the special policies adopted by the US police that help a drop in crime

2.“Why Crime Rates Fell” is mentioned in the article to tell readers that _____.

A．drug crack can be extremely dangerous

B．crime mapping schemes help the police discover criminals

C．criminals should be strictly sentenced

D．children shouldn’t be allowed to contact lead

3.The sixth reason mentioned in the article implies that _____ tend to commit crimes．

A．children

B．young people

C．the poor

D．crime victims

4.The underlined word “offset” most probably mean _____.

A．reduced

B．caused

C．imposed

D．demanded