677

[nationalfuel]

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
i can't understand why A is wrong.
i am thinking whether the word "visible" changes the meaning of the whole sentence.
The answer D that i am confused is that ok to use "at" right here

[reachac]

Sighted at is the correct usage and not sighted on. Hence the answer

[moadhia]

the correct answer is A .. this is straight from OG

[x2suresh]

Yeap this is from OG..



OG explanation

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 typically introduces a subordinate clause, which has a subject and a verb, but here 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 sunspot or dark spots, becomes unclear.

[x2suresh]

I thought below explantion for Preposition is good..

I found this notes from another forum.



Confusion is related to prepositions "At", "On" and "In".
Just to brush up the concept:
Prepositions differ according to the number of dimensions they refer to:

Point
Prepositions in this group indicate that the noun that follows them is treated as a point in relation to which another object is positioned.

Surface
Prepositions in this group indicate that the position of an object is defined with respect to a surface on which it rests.

Area/Volume
Prepositions in this group indicate that an object lies within the boundaries of an area or within the confines of a volume.

In light of these descriptions, at, on, and in can be classified as follows:
at ....... point
on ....... surface
in ....... area/volume

"At" calls for further comment.
Because it is the least specific of the prepositions in its spatial orientation, it has a great variety of uses.
Here are some of them:

location
Tom is waiting for his sister at the bank.

destination
We arrived at the house.

direction
The policeman leaped at the assailant.

To know more click below link:
https://owl.english.purdue.edu/handouts/ ... prep2.html