大全677

creditadvice

677. 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
(B) are visible as dark spots that never have been sighted on the surface of the Sun
(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
(E) appear as dark spots on the Sun’s surface, which have never been sighted on
答案是C。可是为什么是although never sighted at, 偶觉得应该是although never been sighted at才对啊

jnlvo

只是表一般状态，用sighted at正合适。been显得多余。

creditadvice

偶觉得应该是被动才对啊，sunspots又不能自己看见自己，总是被看见的罗？

请指教

rt316

当条件状语的主语和主句的主语一致时，条件状语的主语和be动词可以一起省略。所以C的结构是可以接受的；此外，虽然at/on the quatorat都可以使用，但at the poles是比较合适的介词结构；所以用at替代所有的介词，可行；另外，are visible as dark spots on the surface中on the surface修饰dark spots不合适，事实上，太阳表面并没有dark spots，而只是我们看到的好像有dark spots；

sofarsgood

677. 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
(B) are visible as dark spots that never have been sighted on the surface of the Sun
(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
(E) appear as dark spots on the Sun’s surface, which have never been sighted on
答案是C。可是为什么是although never sighted at, 偶觉得应该是although never been sighted at才对啊

我觉得A是意思表达最清楚的一个，原因：

1. visible as 我在OG中见过这种表达，

2. 既然有never，用完成时较好，C省的没有道理

3. at 和 on 我认为on也说得过去，何况 我觉得C有歧义

C) appear on the surface of the Sun as dark spots although never sight ed at the Sun’s poles or equator. 好像是在说没有在sun's poles or equator 看见sunspots。

sofarsgood

我找到OG上关于visible as的那道题了

68. Often visible as smog, ozone is formed in the atmosphere from hydrocarbons and nitrogen oxides, two major pollutants emitted by automobiles, react with sunlight.

(A) ozone is formed in the atmosphere from

(B) ozone is formed in the atmosphere when

(C) ozone is formed in the atmosphere, and when

(D) ozone, formed in the atmosphere when

(E) ozone, formed in the atmosphere from

IDAISY

just went through all discussions, the only point that can convince me is that 'at' is preferable over "on"

but is "on the Sun's poles and equators" a definite mistake? I have no clear concept on prep. and often misuse them.

is there any further difference between A and C?

Avantasia

同意楼上的观点。

从纯语法角度考虑，我觉得AC差异甚微，也许就那个on和at有点区别。

ogram

而且C 选项把“as dark spots”放在“Sun”的后面，也会产生歧义，让人以为“Sun”是“dark spots”

估计出这道题的GMAC委员当时正好和他老婆做完爱，出题时逻辑思维不够清晰

snowjing

以下是引用Avantasia在2005-6-3 19:42:00的发言：

同意楼上的观点。

从纯语法角度考虑，我觉得AC差异甚微，也许就那个on和at有点区别。

个人理解C比A好.

on the surface of the Sun 应该修饰Sunspots, 而A中的"on the surface of the Sun"有修饰dark spots之嫌.

Open to discuss.