作者：英吉
Developed by Pennsylvania's Palatine Germans about 1750, they made Conestoga wagons with high wheels capable of crossing rutted roads, muddy flats, and the nonroads of the prairie and they had a floor curved upward on either end so as to prevent cargo from shifting on steep grades.
(A) they made Conestoga wagons with high wheels capable of crossing rutted roads, muddy flats, and the nonroads of the prairie and they had a floor curved upward on either end so as to prevent
(B) they made Conestoga wagons, which had high wheels capable of crossing rutted roads, muddy flats, and the nonroads of the prairie, and floors curved upward on their ends so that they prevented
(C) Conestoga wagons, with high wheels capable of crossing rutted roads, muddy flats, and the nonroads of the prairie, and had a floor that was curved upward at both ends to prevent
(D) Conestoga wagons had high wheels capable of crossing rutted roads, muddy flats, and the nonroads of the prairie, and a floor that was curved upward at both ends to prevent
(E) Conestoga wagons had high wheels capable of crossing rutted roads, muddy flats, and the nonroads of the prairie and floors curving upward at their ends so that it prevented
原文意思：被一种人发展，一个东西具有一大堆特点
题目分析：前面说developed by，后面必须告诉我谁被develop了，而AB后面用they没有马上告诉我，不好。
C前面用with high wheels后面加and had a floor前面是介词短语后面是句子，前后不能用and连接，干掉。
D说wagons有一大堆东西，写的比较并列，留着。
E乍一看还凑合，但是后面用curving而D用was curved一个主动一个被动，floor自己做不出curve这个动作，只能用被动，选D。
