Known to its considerable opposition as "Seward's Folly", the purchase of Alaska was not unlike that of the Louisiana territory, which provided the United States with new land, a strategic military position, and control of the entire Mississippi River valley.
(A) not unlike that of the Louisiana territory, which provided
(B) not unlike the Louisiana territory, which provided
(C) like the Louisiana territory, which provided
(D) like that of the Louisiana territory for providing
(E) as that of the Louisiana territory for providing
答案选A ，因为D“for providing"不知带是指purchase of Alaska 还是 that of Louisiana。
但是我觉得“for providing"紧跟that of Louisiana ,难道是不是修饰他的吗？
还有"which provided"之前为什么要有逗号，我怎么觉得逗号反而使得"which"指向了purchase of Alaska
求高手解答，谢谢 作者: 287151319 时间: 2015-1-5 00:34
the purchase of Alaska was like that of the Louisiana territory for providing the United States with new land, a strategic military position, and control of the entire Mississippi River valley.
如果这样，for providing表示原因就修饰的是the purchase of Alaska为什么像that of the Louisiana territory的原因，表意错误。
which引导非限定修饰，用逗号隔开，建议看看mahattan sc 5th作者: lululuna 时间: 2015-3-30 15:32
D是一定不对的，the purchase of Alaska 与the purchase of Lousiana 相似点，就control of Mississippi River Valley, 是不可能的。D可以理解为，购买Alaska也为美国提供了 密西西比河谷的控制权，但Alaska离开Mississippi river十万八千里呐；在此，provide 后面的内容，仅用于形容Louisiana ，不容易引起misunderstanding.
拙见，有错请包涵。