1，Spurred by the phenomental growth of the city of Chicago after the Civil war, Illinois became ? A, that a major industrial state; B, to a major industrial state; C, a major industrial state; D, to be a major industrial state. 答案是D， 但是C 有可能也对吗？
2，[Identical ]twins are always [of the] same sex, [resemblance] one another very [closely], and have similar fingerprints and blood groups. 答案是C， 应该怎么改？为什么不是B？
3，Working [by] chemical reaction, and being [independence] of atmospheric oxygen, rockets are used [to power] interplanetary [space] vehicles. 答案是B，为什么不是A，应该怎么改？
4,Oak trees furnish more [timber annually] in the U.S. than [any of] other broad-leaved tree and are [second only] to conifers [in tota]l lumber production. 答案是B， 为什么不是C（the second ）？应该怎么改？
5, Intricate [choreographer] emphasized the beauty and virtuosity [of the ] nineteenth-century prima ballerina, while the male [dancer functioned] only as her partner [until] the twentieth century. 答案是A，怎么改？为什么不是B？
6， The New York City Ballet has been ? of United States classical ballet companies since its inception in 1946. A, the consistently creative most; B, consistently creative the most; C, most creative the consistently; D, the most consistently creative. 答案是B， 为什么，怎么翻译？