已知集合A={x|x²-ax≤x-a，a∈R}，B={x|4x-x²-3≥0}，若A∪B=B，求实数a的取值范围．

A person named Bernard Jackson today is a free man, but he has many bitter memories. He spent five years in prison after a jury (陪审团) wrongly convicted (判处……有罪) him of raping two women. At Jackson’s trial, although two witnesses testified that Jackson was with them in another location at the time of the crime, he was convicted anyway. Why? The jury believed the testimony (证词) of the two victims, who positively identified Jackson as the man who had attacked them. The court eventually freed Jackson after the police found the real criminal.

Many factors influence the accuracy of eyewitness testimony. For instance, witnesses sometimes see photographs of several suspects before they try to identify the person they saw in a group of people. They can become confused by seeing many photographs of similar faces. The number of people in the group, and whether it is a person or a photograph, may also affect a witness’s decision. People sometimes have difficulty identifying people of other races. The questions the police ask witnesses also have an effect on them.

Many people believe that police officers are more reliable than ordinary people. Psychologists decided to test this idea, and they discovered that it is not true. Two psychologists showed a film of crimes to both police officers and civilians. The psychologists found no difference between the police and the civilians in correctly remembering the details of the crimes.

Despite all the possibilities for inaccuracy, courts cannot leave out eyewitness testimony from a trial. American courts depend almost completely on eyewitness testimony to resolve (决定) court cases. Sometimes it is the only evidence to a crime, such as rape. Furthermore, eyewitness testimony is often correct. Although people do sometimes make mistakes, and convict innocent people, more importantly, eyewitness testimony has rightly convicted a larger number of guilty people.

American courts depend on the ability of the twelve jurors, and not the judges, to determine the accuracy of the witness’s testimony. It is their responsibility to decide if a certain witness could actually see, hear and remember what happened.

小题1:Bernard Jackson was found guilty and sentenced 5 years’ prison because          .

A．the police discovered evidence leading to his guilt

B．he admitted the crime of raping two women

C．the victims insisted that he was the attacker

D．the eyewitness proved the victims’ testimony小题2:The following statements may be the reasons for why sometimes the eyewitness’ testimony is not accurate EXCEPT          .

A．the eyewitness is confused by the police’s questions

B．the eyewitness is shown photos of many similar faces

C．the eyewitness lacks the professional help from police

D．the eyewitness can’t identify people of other races clearly小题3:An inaccurate eyewitness testimony may lead to        .

A．the misunderstanding of the case

B．the disbelief in the court

C．the disrespect for the eyewitness

D．the conviction of an innocent person小题4:Eyewitness testimony is important because        .

A．it can be relied on to detect criminals in all cases.

B．it is sometimes the only way to resolve court cases.

C．it is sometimes the only clue for police investigation.

D．it is more reliable than physical evidences to a crime.小题5:According to the text, we can infer that          .

A．police identification is more reliable than that of the ordinary people

B．eyewitness testimony is valuable, though sometimes incorrect.

C．crime victims often fail to give positive identification of the suspects

D．the jury relies on the judge rather than the eyewitness for a decision