In the 1920s demand for American farm products fell, as European countries began to recover from World War I and instituted austerity (紧缩) programs to reduce their imports. The result was a sharp drop in farm prices. This period was more disastrous for farmers than earlier times had been, because farmers were no longer self-sufficient. They were paying for machinery, seed, and fertilizer, and they were also buying consumer goods. The prices of the items farmers bought remained constant, while prices they received for their products fell. These developments were made worse by the Great Depression, which began in 1929 and extended throughout the 1939s.

In 1929, under President Herbert Hoover, the Federal Farm Board was organized. It established the principle of direct interference with supply and demand, and it represented the first national commitment to provide greater economic stability for farmers.

President Hoover's successor attached even more importance to this problem. One of the first measures proposed by President Franklin D. Roosevelt when he took office in 1933 was the Agricultural Adjustment Act, which was subsequently passed by Congress. This law gave the Secretary of Agriculture the power to reduce production through voluntary agreements with farmers who were paid to take their land out of use. A deliberate scarcity of farm products was planned in an effort to raise prices. This law was declared unconstitutional by the Supreme Court on the grounds that general taxes were being collected to pay one special group of people. However, new laws were passed immediately that achieved the same result of resting soil and providing flood-control measures, but which were based on the principle of soil conservation. The Roosevelt Administration believed that rebuilding the nation's soil was in the national interest and was not simply a plan to help farmers at the expense of other citizens. Later the government guaranteed loans to farmers so that they could buy farm machinery, hybrid (杂交) grain, and fertilizers.

26.The author says that the powerful computers of today ______.
   A) are capable of reliably recognizing the shape of an object
   B) are close to exhibiting humanlike behavior
   C) are not very different in their performance from those of the 50's
   D) still cannot communicate with people in a human language

27.The new trend in artificial intelligence research stems from ______.
   A) the shift of the focus of study on to the recognition of the shapes of objects
   B) the belief that human intelligence cannot be duplicated with logical, step-by-step programs
   C) the aspirations of scientists to duplicate the intelligence of a ten-month-old child   
   D) the efforts made by scientists in the study of the similarities between transistors and brain cells

28.Conrad and his group of AI researchers have been making enormous efforts to ______.
   A) find a roundabout way to design powerful computers
   B) build a computer using a clever network of switches
   C) find out how intelligence developed in nature
   D) separate the highest and most abstract levels of thought

29.What's the author's opinion about the new AI movement?
   A) It has created a sensation among artificial intelligence researchers but will soon die out.
   B) It's a breakthrough in duplicating human thought processes.
   C) It's more like a peculiar game rather than a real scientific effort.
   D) It may prove to be in the right direction though nobody is sure of its future prospects.

30.Which of the following is closest in meaning to the phrase "the only game in town" (Line 3, Para. 4)?
   A) The only approach to building an artificially intelligent computer.
   B) The only way for them to win a prize in artificial intelligence research.
   C) The only area worth studying in computer science.
   D) The only game they would like to play in town.