2. The passage suggests that before the early 1970's, which of the following was true of the study by historians of the working class in the United States?

　　(A) The study was infrequent or superficial, or both.

　　(B) The study was repeatedly criticized for its allegedly narrow focus.

　　(C) The study relied more on qualitative than quantitative evidence.

　　(D) The study focused more on the working-class community than on working-class culture.

　　(E) The study ignored working-class joblessness during the Great Depression.

　　3. According to the passage, which of the following is true of Keyssar's findings concerning unemployment in Massachusetts?

　　(A) They tend to contradict earlier findings about such unemployment.

　　(B) They are possible because Massachusetts has the most easily accessible historical records.

　　(C) They are the first to mention the existence of high rates of geographical mobility in the nineteenth century.

　　(D) They are relevant to a historical understanding of the nature of unemployment in other states.

　　(E) They have caused historians to reconsider the role of the working class during the Great Depression.

　　4. According to the passage, which of the following is true of the unemployment rates mentioned in line 15

　　(A) They hovered, on average, around 15 percent during the period 1870-1920.

　　(B) They give less than a full sense of the impact of unemployment on working-class people.

　　(C) They overestimate the importance of middle class and white-collar unemployment.

　　(D) They have been considered by many historians to underestimate the extent of working-class unemployment.

　　(E) They are more open to question when calculated for years other than those of peak recession.