逗号与连词连用的并列结构

peter3008

最近做了老prep的题目,发现平行与句子结构为先这句话果真没错,不过",and/but"这种结构我还有抱有疑问,请NN帮忙解答一下:
如prep2-138题 正确句子:

A middleweight black hole weighs in at roughly 500 solar massess,hundreds of times more massive than the lightweight black holes produced by the collapse of individual stars, but thousands or even millions of times less massive than the heavyweight giants that lurk in the centers of galaxies.

如果but前去掉"," 句子是hundreds of times more massive than the lightweight black holes produced by the collapse of individual stars but thousands or even millions of times less massive than the heavyweight giants that lurk in the centers of galaxies. 这样也对吗? 尽管句子很长,不顺眼,但是语法,逻辑上好像没有错误. 我自己感觉好像这样并列更紧密点,不会产生歧义.

如果改成 hundreds of times more massive than the lightweight black holes produced by the collapse of individual stars ,but it is thousands or even millions of times less massive than the heavyweight giants that lurk in the centers of galaxies. 那么but后面的句子就与主句并列了,改变了句子的层次,所以是错的.所以我们在碰到but,and 加" ," 的情况下,要判断什么跟什么并列.

求NN帮助,不甚感激~

peter3008

我自己来吧,今天花实践总结了一下:希望可以抛砖引玉,大家讨论
连词与逗号的总结:
OG12th P735 第100题 这个是做连词连句子
This whole
construction, Like the planets, the stars are in
motion, some of them at tremendous speeds, is a main
clause and must be followed by a comma before a
coordinating conjunction (such as yet or but)
introduces a second main clause.

P731 第92题 这个就是连两个不是句子的
A comma, not a semicolon, should
separate the two parallel parts of the contrast 不过貌似好像没有说一定要comma。。。。
P744 第116题
To describe this apparent
contradiction and to avoid a comma splice, the
clauses should be joined by the conjunction but.
(http://forum.chasedream.com/GMAT_SC/thread-457336-1-1.html)
116. Mauritius was a British colony for almost 200 years, excepting for the domains of administration and teaching, the English language was never really spoken on the island
A. excepting for
B. except in
C. but except in
D.but excepting for
E. with the exception of
OA C...

92.The energy source on Voyager 2 is not a nuclear
reactor, in which atoms are actively broken apart;
rather a kind of nuclear battery that uses natural
radioactive decay to produce power.
(A) apart; rather
(B) apart, but rather
(C) apart, but rather that of
(D) apart, but that of
(E) apart; it is that of
OA:B   not A, but B;    not A, but rather B;   A, not B;   A, but rather B. 固定用法  见上面的not…but, 与 do not….but (实际是but表转折)的区别.

100.The stars, some of them at tremendous speeds, are in motion just as the planets are, yet being so far away from the Earth that their apparent positions in the sky do not change enough for their movement to be observed during a single human lifetime.
A) The stars, some of them at tremendous speeds, are in motion just as the planets are, yet being
B) Like the planets, the stars are in motion, some of them at tremendous speeds, but they are
C) Although like the planets the stars are in motion, some of them at tremendous speeds, yet
D) As the planets, the stars are in motion, some of them at tremendous speeds, but they are
E) The stars are in motion like the planets, some of which at tremendous speeds are in motion but
OA is B

I)连接2个main clause的一定要用” , and/but”的形式

II)A comma should separate the two parallel parts of the contrast 逗号的作用分割句群, sth is not A , but rather B
如果改为 Sth is not A but rather B 我认为也是可以的 (不是重要考点) (例题见Laos) A but B也是可以的,最好A,B都是简单的名词性短语,不要是仅次main clause的分句这些,如果是这些我个人觉得还是要用 comma separate,但是并列不可产生歧义.
III)To describe apparent contradiction and to avoid a comma splice, the clause should be joined by the conjunction but.
"X was Y, except in Z" would be a sentence by itself.
therefore, "X was Y, except in Z, A was B" is a run-on (you can't tag 2 complete sentences together with a comma)
but在这里的作用是作为连词连接两个独立的分句, 如果没有but，前句是："Mauritius was a British colony for almost 200 years" 主语是Mauritius；后句是：“the English language was never really spoken on the island” 主语是the English language，前后句主语不一致，所以必须使它们成为两个独立的句子，连词就能实现这个功能. 即是我们所说的run-on.

do A, do B, and do C.句子1, 句子2, and 句子 3.  比较特殊的情况: SVO, 插入语, and/but VO 依据插入语的形式来看.(详见p35题目)
注意一点的是, 并列句子中的主语省略和这样并列会不会造成并列引起的歧义的问题
56题: intar has moved away from the Spanish classics and now draws on the works of contemporary Hispanic authors.
     intar has moved away from the Spanish classicsk, and now it draws on the works of contemporary Hispanic authors.
“,and/but”结构是连接2个main clause的, 对于可以省略主语的并列,不需要加上” ,” comma
如果改成: intar has moved away from the Spanish classics and now draws on the works of contemporary Hispanic authors. 就不对了.因为 draws 与moved 这2个动作并列,同一个主语,不需要用逗号分开,
假如是: intar has moved away from the Spanish classics, 插入 语, and now draws on the works of contemporary Hispanic authors.这就对了

Laos has a land area about the same as Great Britain but only 4 million in population, where many are members of hill tribes ensconced in the virtually inaccessible mountain valleys of the north.
A. about the same as Great Britain but only 4 million in population, where many
B. of about the same size as Great Britain is, but in Laos there is a population of only 4 million, and many
C. that is about the same size as Great Britain’s land area, but in Laos with a population of only 4 million people, many of them
D. comparable to the size of Great Britain, but only 4 million in population, and many
E. comparable to that of Great Britain but a population of only 4 million people, many of whom
Ans is E
laos has a land area comparable to that of Great Britain but a population of only 4 million people, many of whom...
so, basically, laos has X but Y, where X and Y show some kind of contrast with each other.
这题虽然有转折,但是在之前加","comma逗号
(http://www.manhattangmat.com/forums/laos-has-a-land-area-t5749.html)

P35. In laboratory rats, a low dose of aspirin usually suffices to block production of thromboxane, which is a substance that promotes blood clotting, but not seriously interfering with the production of prostacyclin, which prevents clotting.
(A) which is a substance that promotes blood clotting, but not seriously interfering
(B) a substance that promotes blood clotting, but not seriously interfering
(C) a substance that promotes blood clotting, but does not seriously interfere
(D) which is a substance to promote blood clotting, but does not seriously interfere
(E) which is a substance that promotes blood clotting, but not a serious interference
OA:C
这题: SVO, 插入语, and/but VO 中 插入语为which VO, 笔记上说, 选项D: which V1O, but V2O 产生歧义,是V1和V2并列的嫌疑.
而选项E: but 则省略了相同主语与谓语, which is a substance that promotes blood clotting, but (which is ) not a serious interference
而同位语却不会产生歧义,同位语优于定语从句. 选项C: a substance that promotes blood clotting, but does not seriously interfere 却不会产生
Promote与interfere并列的嫌疑,因为这个同位语如同插入语, 而定语从句是修饰语句, which is a substance to promote blood clotting, but does not seriously interfere, 根据OG上面的II) 和 III) 讲的，a comma should separate the two parallel parts of the contrast 和 To describe apparent contradiction and to avoid a comma splice, the clause should be joined by the conjunction but. 即: 这句话有2中不同理解意思,
A)    a low dose of aspirin usually suffices to block production of thromboxane, (which is a substance to promote blood clotting), but does not seriously interfere .  suffices与interfere 并列
B)    a low dose of aspirin usually suffices to block production of thromboxane, (which is a substance to promote blood clotting, but does not seriously interfere)  is 与 interfere并列, but连接的是分句表示转折
再看2个改写
C)    a low dose of aspirin usually suffices to block production of thromboxane, which is a substance to promote blood clotting but does not seriously interfere明显的表示is 与 interfere 并列,语法对,但是逻辑意思不对
D)    a low dose of aspirin usually suffices to block production of thromboxane, which is a substance to promote blood clotting, but a low dose of aspirin (或者使用合理代词) does not seriously interfere.  Which就变为插入语了,语法逻辑都对,不过不简洁.
(C,D2个选项是我自己改写的,仅供参考)

相比较之下,同位语清楚简洁,不产生并列所产生的歧义.

人淡如菊悠悠

顶一个，正纠结呢  很受用啊~