39. What does the speaker mainly discuss?
40. What is the purpose of the talk?
41. What did the Hohokam do with their pottery?
42. What does the speaker say about the way the Hohokam pottery was made?
43---45 A talk in an American history class.
I'm going to introduce two current points of view about the motivation for writing the United States
Constitution back in 1787. The first one is called the idealist view. The idealists basically believe that the
writers of the Constitution were motivated by ideas. Which ideas? The ideas of the revolutionary war, such as liberty and democracy. The idealists remind that the young country had a lot of problems: an economic
depression, a large war debts, lawlessness and trade barriers between the states. They argue that the
representatives needed to control these problems in order for the United States to survive. The other point of view is the economic view. The economic view is that the writers of the Constitution were concerned about their own financial interests. According to them most people were living wealth for the wealthiest people were afraid of losing their money. The writers wanted a strong central government that would promote trade protect private property and perhaps most of all collect taxes to pay off the United States' large war debts. Because a number of those who wrote the constitution had loaned money to the government during the revolution. Which view is correct? Well , historians who wrote during the calm and prosperous 1950s found reasons to believe the idealist view. Those who wrote during the trouble of 1960s found support for the economic view point. I'd say that neither view is complete, both the idealist and the economic perspective contribute a part to the whole picture.
43. what is the talk mainly about?
44. According to the economic view, who benefited the most from the new Constitution?
45. What can be inferred about the views of the historians?

46---50 Part of a speech on birds by a biologist.
Many egg-laying animals merely lay their eggs and leave. Turtles for instance, the eggs hatch on their own. The current theory about birds is that the earliest birds did just that when they were cold-blooded creatures living in warm places. However when they became warm-blooded creatures living in cold places they had to remain on the eggs to keep them warm. The process we call incubation. For this they needed a place --- a nest. Very likely the first nests were just primitive depressions scrape into the ground. Even now many species still lay eggs in this sort of crude nests. In fact every spring a mother killdeer lays her in some pebbles along the edge of the parking lot just outside this building. Primitive nests on the ground were fine for some birds but others began to elevate their nests in branches perhaps to avoid predators. These early elevated nests were probably loose platf nest, you know, like a robin's nest.
46. What is the main topic of the talk?
47. What evolutionary change in birds led to nest building?
48. According to the speaker, where were the first bird's nests located?
49. What is the killdeer's nest in parking lot an example of?
50.According to the speaker, what is a possible reason that birds began to build nests in trees?

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