问题
单项选择题
1，4，13，40，121，（）
A．1093
B．364
C．927
D．264
答案
参考答案：B
解析：
二级等差变式。差为等比数列：3,9,27,81,(243)，故121+243=364，选 B
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1，4，13，40，121，（）
A．1093
B．364
C．927
D．264
参考答案：B
解析：
二级等差变式。差为等比数列：3,9,27,81,(243)，故121+243=364，选 B
| 完形填空 Shopping habits in the United States have changed greatly in the last quarter of the 20th century.Early in the 1900s most American towns and cities had a Main Street.Main Street was always in the heart of a town.This street was __1__on both sides with many __2__ businesses.Here, shoppers walked into stores to look at all sorts of merchandise:clothing, furniture, hardware, groceries.__3__, some shops offered __4__.These shops included drugstores, restaurants, shoerepair stores, and barber or hairdressing shops.__5__ in the 1950s, a change began to __6__.Too many automobiles had crowded into Main Street while too few parking places were __7__ shoppers.Because the streets were crowded, merchants began to look with interest at the open spaces __8__the city limits.Open space is what their cardriving customers needed. And open space is what they got when the first shopping centre was built.Shopping centres, or rather malls, __9__ as a collection of small new stores __10__crowded city centres.__11__ by hundreds of free parking space, customers were drawn away from __12__ areas to outlying malls.And the growing __13__ of shopping centres led __14__to the building of bigger and better stocked stores.By the late 1970s, many shopping malls had almost developed into small cities themselves.In addition to providing the __15__ of one stop shopping, malls were transformed into landscaped parks, with benches, fountains, and outdoor entertainment. | ||||
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