| [求助]几道有疑惑的语法题，多谢
Q1 Emily Dickinson’s letters to Susan Huntington Dickinson were written over a period beginning a few years before Susan’s marriage to Emily’s brother and ending shortly before Emily’s death in 1886, outnumbering her letters to anyone else.
A) Dickinson were written over a period beginning a few years before Susan’s marriage to Emily’s brother and ending shortly before Emily’s death in 1886, outnumbering
B) Dickinson were written over a period that begins a few years before Susan’s marriage to Emily’s brother and ended shortly before Emily’s death in 1886, outnumber
C) Dickinson, written over a period beginning a few years before Susan’s marriage to Emily’s brother and that ends shortly before Emily’s death in 1886and outnumbering
D) Dickinson, which were written over a period beginning a few years before Susan’s marriage to Emily’s brother, ending shortly before Emily’s death in 1886, and outnumbering
E) Dickinson, which were written over a period beginning a few years before Susan’s marriage to Emily’s brother and ending shortly before Emily’s death in 1886, outnumber
Key: E, but why not A, 我认为 E中的, which 不太好， which 不是应该就近修饰吗
Q2 The agreement, the first to formally require industrialized countries to cut emissions of gases linked to global warming, is a formal protocol by which 38 industrialized countries must reduce emissions of these gases by 2012 or face heavy penalties.
A）by which
B）for which
C）under which
D）such that
E）wherein
Key： C under which，不明白是什么意思，under 是不是有其他用法
Q3 Medicare, the United States government’s health insurance program for the elderly and disabled, covers the full cost of home health care, but not with other nonhospital services where 20 percent of the costs must be paid by beneficiaries.
B）but not of other nonhospital services, making beneficiaries pay 20 percent of the costs
C）but not of other nonhospital services, for which beneficiaries must pay 20 percent of the costs
Key：C，B不对的理由我认为是 v+ing 做伴随状语表结果，应表示前一句话从整体上对后一分句的影响，而不是其中某一部分（but not of other nonhospital services）对后面的影响，不知这样理解对吗？
Q4 Construction of the Roman Colosseum, which was officially known as the Flavian Amphitheater, began in A.D. 69, during the reign of Vespasian, was completed a decade later, during the reign of Titus, who opened the Colosseum with a one-hundred-day cycle of religious pageants, gladiatorial games, and spectacles.
A）which was officially known as the Flavian Amphitheater, began in A.D. 69, during the reign of Vespasian,
B）officially known as the Flavian Amphitheater, begun in A.D. 69, during the reign of Vespasian, and
C）which was officially known as the Flavian Amphitheater, began in A.D. 69, during the reign of Vespasian, and
D）officially known as the Flavian Amphitheater and begun in A.D. 69, during the reign of Vespasian it
E）offically known as the Flavian Amphitheater， which was begun in AD 69，during the regin of Vespasian
key：C， but why not B，我认为B比 C更简洁
Q5 Whereas lines of competition are clearly defined in the more established industries, in the Internet industry they are blurred and indistinct, as companies that compete one day may be partners the next.
A）Whereas lines of competition are clearly defined in the more established industries, in the Internet industry they are blurred and indistinct, as companies that compete
B）Although the lines of competition are clearly defined in industries that are more established， they are blurred and indistinct in the Internet industry， as competing companies
C）The line of competition are clearly defined in the more established industries， unlike the Internet where they are blurred and indistinct， as companies that compete
D）Unlike more established industries， where the lines of competition are clearly defined， they are blurred and indistinct in the Internet industry， as companies that compete
E） Unlike more established industries， with clearly defined lines of competition， those of the Internet industry are blurred and indistinct， as competing companies
Key：B，但我有疑问，that are more established 是不是有些冗长 they 指代是否有歧义
多谢！ | 
