[求助]大全 677

angelavivi

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（C）

(E) appear as dark spots on the Sun’s surface, which have never been sighted on

不懂为什么选C

casualwalk

你很厉害啊，问的题目都是大全和11版OG有争议的题。这道题11版OG说答案是A.

The correct parallel structure in the original sentence emphasizes the contrast between where sunspots are found (are visible...Sun) and where they are not (have ever beensighted...equator). Sunsports is the subject of the sentence, are is the verb of the first part of the contrast and have been sighted is the verb of the the second. The adjective visible is a complement and is a parallel to the past participle sighted. Both parts of the sentence conclude with phrases indicating location.The contrast itself is indicated by the conjunction but.

A.correct. This sentence clearly and correctly draws a contrast between where sunspots are found and where they are not

B.Changing the modifying clause so that that never...Sun distorts the meaning of the sentence; the contrast is lost

C.Although typically introduces a subordinate clause, which has a subject and a verb, but here there is no subject and sighted is not a complete verb

D.Although usually introduce a subordinate clause, but there is no subject of the clause and having been sighted is not a complete verb phrase

E.The relative pronoun which should immediately follow its referent; here which illogically follows surface, and its intended referent, either sunspots or dark spots, becomes unclear