|
39. Why does the woman collect coins?
40. Why were letters VDB on pennies?
41. What was one of reasons the speaker collected coins as a teenager?
42. What will the speaker do next? Question 43-46 Listen to talk from a biology class
Today I want to talk to you about wasps and their nests. You'll recall the biologist divide species of wasps into two groups: solitary and social. Solitary wasps as the name implies do not live together with other wasps. In most species the male and female get together only to mate and then the female does all the work of building the nest and providing the food for the offspring by herself. Solitary wasps usually make nests in the ground and they separate the chambers for the individual offspring with bits of grass, stone or mud, whatever is handy. What about social wasps? They form a community and work together to build and maintain the nest. A nest begins in the spring when the fertile female called the queen builds the first few compartments in the nest and lay eggs. The first offspring are females but cannot lay eggs. These females called workers. They build a lot of new compartments and the queen lays more eggs. They also care for the new offspring and defend the nest with their stingers. By the way only the female wasps have stingers. Most social wasps make nest of paper. The female produces the paper by chewing up plant fibers or old wood. They spread the papers in thin layers to make cells, in which the queen lays her eggs. Most of you I'm sure have seen these nests suspended from trees. They may also be built under the ground in abandoned rodent burrows.
43. Who build the nest of solitary wasps?
44. Why the female wasps are more dangers to people than the mal wasps are?
45. What is the main function of the queen?
46. What are the nests of social wasps made of? Question 47-50 Listen to a talk in class about United States history
One of the most popular myths about the United States in the 19th Century was that of the free and simple life of the farmer. It was said that the farmers worked hard on their own land to produce whatever their families' needed. They might sometimes trade with their neighbors, but in general they could get along just fine by relying on themselves, not on commercial ties with others. This is how Thomas Jefferson idealized the farmer at the beginning of the 19th century. And at that time, this may have been close to the truth especially on the frontier. But by the mid century sweeping changer in agriculture were well under way as farmers began to specialize in the raising of crops such as cotton or corn or wheat. By late in the century revolutionary advances in farm machinery has vastly increased production of specialized crops and extensive network of railroads had linked farmers throughout the country to markets in the east and even overseas. By raising and selling specialized crops, farmers could afford more and finer goods and achieved a much higher standard of living but at a price. Now farmers were no longer dependent just on the weather and their own efforts, their lives were increasing controlled by banks, which had powder to grant or deny loans for new machinery, and by the railroads which set the rates for shipping their crops to market. As businessmen, farmers now had to worry about national economic depressions and the influence of world supply and demand on, for example, the price of wheat in Kansas. And so by the end of the 19th century, the era of Jefferson's independent farmer had come to a close.
| 
