问答题Passage 1　　Historians of the war can be 1 into two schools. The 2 considers that it was the unavoidable outcome of conflicting interests between Northern and Southern states. The second blames it 3 political leaders for __4__ to avert an unnece

Passage 1　　Historians of the war can be  1 into two schools. The  2 considers that it was the unavoidable outcome of conflicting interests between Northern and Southern states. The second blames it  3  political leaders for __4__ to avert an unnecessary war.　　Analysts are also divided on whether the issue of slavery was the primary cause of the war,  5 a symptom of other more critical differences—especially sectional interests and the doctrine of states’ rights—between the North and South  6 had been developing since the formation of the American republic.　　The fundamental distinction was economic. In the early 1840s the Northern states began the process of industrialization, modernizing their society to  7 the demands of economic change. 8 conclusion, the slogan of Abraham Lincoln’s Republican party, “free labor, free land, free man” encapsulated the ideology of valuing the freedom of individuals to grasp the opportunity 9 economic self-advancement in a booming, expanding society.　　The Southern states remained stubbornly agricultural 10 economically and socially. It was a backward-looking way of life of tall white mansions on great plantations dependent on a labour system which made slaves of approximately 4 million black Americans.　　America was thus divided by economic structure, and was led into fratricidal (杀同胞的) warfare by  11 series of political clashes. The most common cause was the future of the West. The crises  12 California’s admission in 1850 and over Kansas-Nebraska in 1854 were typical of the divergent economic interests of North and South in relation to the  13 .　　The North wanted free land for independent labour in the same new territories  14 the South sought to perpetuate its traditional way of life by extending slavery. The issue was not the slavery already practised, but the prospect of its extension  15 the West.