OG16 SC19、20、23有几个点不解，请牛牛们指点一下~

SashiRorOko

19. Sunspots, vortices of gas associated with strong electromagnetic activity, are visible as dark spots on the surface of the Sun but have never been sighted on the Sun’s poles or equator.
(A) are visible as dark spots on the surface of the Sun but have never been sighted on
(C) appear on the surface of the Sun as dark spots although never sighted at
(D) appear as dark spots on the surface of the Sun, although never having been sighted at
         
C和D选项都因为“although引导的从句得有主语和谓语动词”排除掉了，可是正确的A选项不是也没有主语嘛？难道是被省略掉了？

20. The commission has directed advertisers to restrict the use of the word “natural” to foods that do not contain color or flavor additives, chemical preservatives, or nothing that has been synthesized.
(A) or nothing that has been
(B) or that has been
(C) and nothing that is
(D) or anything that has been
(E) and anything

借由这个题想问一下，…Foods that do not contain color or flavor additives…和…Foods that do not contain color and flavor additives…这两个短语的意思有什么差异？

23. Discussion of greenhouse effects have usually had as a focus the possibility of Earth growing warmer and to what extent it might, but climatologists have indicated all along that precipitation, storminess, and temperature extremes are likely to have the greatest impact on people.
(A) Discussion of greenhouse effects have usually had as a focus the possibility of Earth growing warmer and to what extent it might,
(B) Discussion of greenhouse effects has usually had as its focus whether Earth would get warmer and what the extent would be,
(C) Discussion of greenhouse effects has usually focused on whether Earth would grow warmer and to what extent,
(D) The discussion of greenhouse effects have usually focused on the possibility of Earth getting warmer and to what extent it might,
(E) The discussion of greenhouse effects has usually focused on whether Earth would grow warmer and the extent that is,

OG的解释上说whether Earth would grow warmer 和 to what extent是平行结构，这个怎么平行了？这不是一个句子和一个短语在平行吗？
而且Discussion of greenhouse effects has usually focused on whether Earth would grow warmer and to what extent这句话是什么意思呢？主要是被to what extent难倒了。

请牛牛们给我指点指点~

薄荷香槟0331

og上解释的是although一般是跟从句的，不是主句，而这句话里although后面是主句所以不对

否定词后面or就是肯定句里and的意思，比如I want A， B and C，如果是否定的话就是I don't want A, B or C

其实to what extent 陈述句的顺序就是extent to what，变成问句把 to what提前嘛~

个人意见啦~

monica1315

19.答案没错啊，C和D是因为although后没主语被排除的，但是A里面用的是but啊
20.or和and的区别很明显啊。明天家长会，你爸或你妈要来。（来一个就行）。明天家长会，你爸和你妈要来。（两个必须都来）。or只要其中满足一个条件就行了，and条件都要满足。
21.to what extent到何种程度。这句话的意思是：对温室效应的讨论通常集中在地球是否变得更暖了以及暖到何种程度。

SashiRorOko

monica1315 发表于 2015-11-11 15:14
19.答案没错啊，C和D是因为although后没主语被排除的，但是A里面用的是but啊
20.or和and的区别很明显啊。明 ...

谢谢层主的解答！
我上初中那会儿，我记得老师在讲or和and前面跟了否定词后，貌似意思会调换还是怎么的。
就像“Foods that contain color 【or】 flavor additives”是“含有色素【或者】添加剂的食物”
如果变成否定“Foods that do not contain color 【or】 flavor additives”就成“不含色素【和】添加剂的食物”了

SashiRorOko

monica1315 发表于 2015-11-11 15:14
19.答案没错啊，C和D是因为although后没主语被排除的，但是A里面用的是but啊
20.or和and的区别很明显啊。明 ...

although是连词，后面一定要接一个完整的句子，这个我明白；可是but在这里也算是连词吧，那它是不是也该带上句子呢？

monica1315

SashiRorOko 发表于 2015-11-16 14:30
谢谢层主的解答！
我上初中那会儿，我记得老师在讲or和and前面跟了否定词后，貌似意思会调换还是怎么的。 ...

对对，你说的没错。我忘记了， or前面有否定词，所以才用or的。

Araken

SashiRorOko 发表于 2015-11-16 14:34
although是连词，后面一定要接一个完整的句子，这个我明白；可是but在这里也算是连词吧，那它是不是也该 ...

其实我觉得CD的意思和原文有出入了，虽然都是转折，但是转折的意思不一样，LZ你体会体会

SashiRorOko

Araken 发表于 2015-11-16 18:43
其实我觉得CD的意思和原文有出入了，虽然都是转折，但是转折的意思不一样，LZ你体会体会 ...

我懂了，多谢层主！

喵兔子

同问这道题  我不明白的是为什么这个地方一定要是平行的结构呢   ?还有E怎么就awkward了。。?

冬天太长

同问第23题