请教几道XDF蓝皮的语法题

Daisy德德

这本书有好多不会，求各位大神帮忙!

1. The sale of government surplus machinery will begin at 9 a.m. and continue until the supply lasts.
A. will begin at 9 a.m. and continue until the supply lasts
B. begins at 9 a.m. and, until the supply lasts, will continue
C. will begin at 9 a.m. and, until the supply lasts, will continue
D. begins at 9a.m. and, as long as the supply may last, it continues
E. will begin at 9a.m. and continue as long as the supply lasts

这题答案是E， 我选了C，and 不是要前后对称么？

2.  In the United States, trade unions encountered far more intense opposition against their struggle for social legitimacy than the organized labor movements of most other democratic nations.A. against their struggle for social legitimacy than
B. in their struggle for social legitimacy than did
C. against their stuggle for social legitimacy as
D. in their straggle for social legitimacy as did
E. when they strggled for social legitimacy than has

答案是B，真心不懂那个did。。。

3. Since 1970 the number of Blacks elected to state and federal offices in the United States has multiplied nearly four times.
A, has multipied nearly four times
B. has almost quadrupled
C. has almost multiplied by four
D. is almost four times as great
E. is nearly fourfold what it was

答案是B。为什么呢？

谢谢各位大神！！！

bejamin1111

1.
continue是不能用将来时的，所以先排除BC；D中：as long as the supply may last, it continues句式用it指代了supply，句式wordy；
关于as long as还是until，我们来看看两者的具体意思；
as long as：provided that 假如，eg As long as you can come by six, I'll be here.
until：在这里是when的意思；我感觉as long as更符合逻辑；所以是E

Daisy德德

bejamin1111 发表于 2013-4-29 22:57
1.
continue是不能用将来时的，所以先排除BC；D中：as long as the supply may last, it continues句式用it ...

谢谢！！！
如果有时间，帮我把下面的几题也解了吧！！！
嘿嘿。

zhuanghaoxin

第一题，助动词will在并列的时候是可以省略的，你要看这句话的意思，如果是until的话，意思就是：这个活动会一直延续直到供给lasts，明显不符合语义。as long as才是对的。
第二题，如果不补出did的话，会让人误解为the organized labor movements of most other democratic nations是在跟 far more intense opposition against their struggle for social legitimacy，就是句子的宾语而不是主语比较。加did明确句子意思。
第三题，时态可以排除D,E。C项如果是被动语态的话少了个been，如果不是就说不通啦；A项，multipied和four times语义重复了。即使这些都不懂，我觉得从第一感觉上看，B是最简洁明了的一个。
这是我的想法，希望你能明白

Daisy德德

zhuanghaoxin 发表于 2013-4-29 23:05
第一题，助动词will在并列的时候是可以省略的，你要看这句话的意思，如果是until的话，意思就是：这个活动 ...

简洁清晰！！！
谢谢你！！！
太棒了！！！

bejamin1111

3. 举个例子，你就懂了
the number of students who go to college has doubled during the past three years!

Daisy德德

bejamin1111 发表于 2013-4-29 23:11
3. 举个例子，你就懂了
the number of students who go to college has doubled during the past three yea ...

O了。。
谢谢！