句子改错，求解！

personperson33UID: 2368236

老师，我有几题不太明白，因为十月考，请尽快回复，谢谢！
1）As children mature, they develop an independence that their parents, who have been responsible for them since they were born, often find difficult to accept.
* l5 o+ |6 [0 s1 _- v. }8 |' x) G答案选的是：no error，但我认为应该是an independence，应把independence改为复数，你怎么认为？
2）Ms. Kovak proudly displayed her research group’s most ingenious invention, a vacuum cleaner that empties its own dust bag when pressing a button.
答案为pressing a button，我选most ingenious invention，我认为因该改为the most ingenious invention，你怎么认为？
3）Although familiar to us from representations in ancient art, war chariots are rare museum artifacts because by the sixth century B.C. they were no longer used in battle.
! d% |- h( O0 i: N2 F2 w答案选no error，我选Although，认为句子不完整，应为，although they were，你怎么认为？
2 ~! W, ^- ?9 ]! R! t4 f% o# k4）A volunteer organization, the Covington Soup Kitchen has been feeding needy families since 1977, annually distributing nearly a million pounds of food each year.
答案为each year，但我认为has been feeding也有点问题，因为has been feeding前面因该有个逗号，为“，has been feeding”
# C) _+ Z. C+ l4 ~3 w  s你怎么认为？

3 J! D. J1 N. @补充一句。这是我5月分考的真题！做的很惨

( @& j) ?  @9 j- p1 w6 \, Q+ _[ 本帖最后由 personperson33 于 2007-9-16 14:29 编辑 ]

ciddyUID: 2263759

1. 不清楚，求大牛
2. 应该D改为pressed a button,应为主语是a vacuum cleaner ，这里的most不是最高级，只是修饰所以不用the
3. 我觉得句子很完整...they are 可以身略
# U& ~0 R, [% h! R1 V5 X0 J- B4. 因该不用"," 因为是同位语,可以直接has been feeding

solv6868UID: 2244156

4. annually与each year意义重复

tolkien_SUID: 2130759

为什么yao 用复数？

lindsay1989UID: 2380557

弱问一句,第3题中"by the sixth century B.C."后为什么不跟过去完成时而是一般过去时?
& ~6 H8 x) }  N: M  p5 ~) ~  l) h) z高中语法里"by"应该是过去的过去,按老师的说法是用they had been no longer used.
请各位大牛指导.

solv6868UID: 2244156

整句是现在时态的，所以用过去式时用一般过去时

HeswingUID: 2218592

4 做同位语，所以不用逗号

tolkien_SUID: 2130759

dui a , a volunteer organization shi tong wei yu, the Covington Soup Kitchen cai shi zhen zheng de zhu yu, bu shi cha ru yu.

windowUID: 2300891

回复 #5 lindsay1989 的帖子
by在这里是例外, 不做"在...时候以前", 而是"在那时", 所以用一般过去即可.
来源可参考新东方黄皮p4.19

stfreezeUID: 2229135

1为啥用复数，independence 作为抽象可数么~
0 M1 V2 \+ t+ K0 p3 ^7 o5 g2.when pressing a XX, when (wat is) pressing a XX~, cleaner? team? or bag?
+ F6 t" q6 @1 @: u7 |7 _3 ~pressed就对了~
0 P- @. h$ U- ]most ingenious invention没错阿~