3.一段中兩個相距較遠的例子說明該段主題句
問題中涉及同一段中兩個例子、而且它們不在一處時，通常它們說明該段主題句。例如，
Mass transportation revised the social and economic fabric of the American city in three fundamental ways. It catalyzed physical expansion, it sorted out people and land uses, and it accelerated the inherent instability of urban life. By opening vast areas of unoccupied land for residential expansion, the omnibuses, horse railways, commuter trains, and electric trolleys pulled settled regions outward two to four times more distant from city centers than they were in the pre-modern era. In 1850, for example, the borders of Boston lay scarcely two miles from the old business district; by the turn of the century the radius extended ten miles. Now those who could afford it could live far removed from the old city center and still commute there for work, shopping, and entertainment. The new accessibility of land around the periphery of almost every major city sparked an explosion of real estate development and fueled what we now know as urban sprawl. Between 1890 and 1920, for example, some 250,000 new residential lots were recorded within the borders of Chicago, most of them located in outlying areas. Over the same period, another 550,000 were plotted outside the city limits but within the metropolitan area. Anxious to take advantage of the possibilities of commuting, real estate developers added 800,000 potential building sites to the Chicago region in just thirty years – lots that could have housed five to six million people.
18. Why does the author mention both Boston and Chicago?
(A) To demonstrate positive and negative effects of growth.
(B) To show that mass transit changed many cities.
(C) To exemplify cities with and without mass transportation.
(D) To contrast their rates of growth
問題中的關(guān)鍵詞Boston與Chicago(為了便于查找，筆者給它們加了下劃線)是兩個例子，它們前面分別有提示詞for example。由于兩個例子位于同一段，而且不在一處，因此只能說明本段主題，也就是首句：Mass transportation revised the social and economic fabric of the American city in three fundamental ways。選項(B)符合此意，為正確答案。
限于篇幅，舉例說明概述題的其他情況，如一段中幾個相連的例子說明的是第一個例子前的那句話，還有“例子在前，概述在后”等情況，恕不詳述。
問題中涉及同一段中兩個例子、而且它們不在一處時，通常它們說明該段主題句。例如，
Mass transportation revised the social and economic fabric of the American city in three fundamental ways. It catalyzed physical expansion, it sorted out people and land uses, and it accelerated the inherent instability of urban life. By opening vast areas of unoccupied land for residential expansion, the omnibuses, horse railways, commuter trains, and electric trolleys pulled settled regions outward two to four times more distant from city centers than they were in the pre-modern era. In 1850, for example, the borders of Boston lay scarcely two miles from the old business district; by the turn of the century the radius extended ten miles. Now those who could afford it could live far removed from the old city center and still commute there for work, shopping, and entertainment. The new accessibility of land around the periphery of almost every major city sparked an explosion of real estate development and fueled what we now know as urban sprawl. Between 1890 and 1920, for example, some 250,000 new residential lots were recorded within the borders of Chicago, most of them located in outlying areas. Over the same period, another 550,000 were plotted outside the city limits but within the metropolitan area. Anxious to take advantage of the possibilities of commuting, real estate developers added 800,000 potential building sites to the Chicago region in just thirty years – lots that could have housed five to six million people.
18. Why does the author mention both Boston and Chicago?
(A) To demonstrate positive and negative effects of growth.
(B) To show that mass transit changed many cities.
(C) To exemplify cities with and without mass transportation.
(D) To contrast their rates of growth
問題中的關(guān)鍵詞Boston與Chicago(為了便于查找，筆者給它們加了下劃線)是兩個例子，它們前面分別有提示詞for example。由于兩個例子位于同一段，而且不在一處，因此只能說明本段主題，也就是首句：Mass transportation revised the social and economic fabric of the American city in three fundamental ways。選項(B)符合此意，為正確答案。
限于篇幅，舉例說明概述題的其他情況，如一段中幾個相連的例子說明的是第一個例子前的那句話，還有“例子在前，概述在后”等情況，恕不詳述。