(Many) a problem concerning the agricultural (production) (have been) solved (this way).（　）

A:Many B:production C:have been D:this way

Where did the movies begin It is often said that they are an American invention. It is not entirely true. The motion picture has been the most international arts. Before the dawn of the twentieth century, inventors in France, England and the United States were among the dozens of men who were trying to develop ways of using photographs to create the effect of motion.
Soon after 1889, when the famous inventor Thomas Edison first showed motion pictures through a device called the kinetoscope (活动电影放映机), other devices for the same purpose appeared all over the world. Edison had solved certain problems, making it possible for other inventors move ahead with their own devices. One other important contribution by Edison was the introduction of 35 mm as the international standard film width.
Why could other inventors succeed in showing motion pictures with their own devices

A:Because they had a device called kinetoscope. B:Because they asked Thomas Edison to help them. C:Because they got a way of using their own devices. D:Because Thomas Edison had successfully solved certain problems.

What two problems can be solved by burning garbage

A:The shortage of energy and air pollution. B:The shortage of energy and the shortage of empty land for holding garbage. C:Air pollution and the shortage of empty land for holding garbage. D:Air pollution and the shortage of fossil fuel.

(If) traffic problems are not solved soon, (driving) (in) cities (becomes) impossible.

A:If B:driving C:in D:becomes

One difficulty has been solved. But another one will（）

A:arise  B:rise  C:arouse  D:arose

The problem was finally solved with our great efforts.

A:clearly B:apparently C:eventually D:naturally

The problem was finally solved with our great efforts.

A:clearly B:apparently C:eventually D:naturally

In many ways, though, definition of such skills is quite unnecessary for an analysis of policing. It is really most unlikely that the average police officer will ever in his career perform or even witness those detective skills that he has enjoyed in countless TV products. The reason for this is simply that the vast majority of crimes are usually either very likely to be solved by routine investigation or they are very unlikely to be solved at all. Fortunately, the clear - up rate for serious crimes tends to be very high. Zander( 1979 )has shown why. In his study of Old bailey cases ,the identity of the defendant(被告) seems to have been reasonably clear in 87% of cases. Morgan (1980 and ongoing)has shown that well over 92% of crimes known to the police are discovered by the public who provide the majority of decisive information. In Morgan’s study, crimes that were" solved" contained in their crime files over twice the amount of qualitative information as crimes that were not" solved". The various bits of information in value in terms of probability of detection, "solving" of the crime. In this, where information was provided by the public during a police interview, the information was believed to the police" since it was felt that in an interview genuine police skills are involved in the collection of information. "Evidently this method can be justified thus, but will necessarily overestimate the police role. Nevertheless, in this analysis of crime files it was shown that in cases where crimes were solves, the public still provided nearly twice the amount of information as the police.
According to the passage, the vast majority of crimes

A:are very likely solve by routine investigation. B:can not be solved simply through routine investigation. C:are unlikely to be cleared up at all. D:can not be solved because the defendants are unknown.