The sentence correction problem is all about understanding the meaning of the sentence.
Essentially, what the sentence says is that seeing X is rare, EVEN THOUGH X is the result of a common event.
The use of the subordinator words “because” or “since” indicates causation.
Using either because or since in the given sentence would be similar to the following sentence:
“Seeing a celebrity in L.A. is rare BECAUSE many celebrities have houses in the city.”
The fact that many celebrities have houses in the city is not the CAUSE of the rare observances.
If I were to say:
“Seeing a celebrity in L.A. is rare EVEN THOUGH many celebrities have houses in the city.”
The sentence would be logical.
Similarly, this sentence is NOT saying that the common events that create a rainbow are the CAUSE of its rare observance.
What the author is trying to get across to the reader is that it seems almost contradictory that we rarely see rainbows. The events that cause rainbows are common place.
Therefore, using “because” or “since” is incorrect in the problem. They do not convey the author’s intended meaning.
Further, the use of the subordinate “although” indicates contrast. For example:
“Although Mary is a cautious driver, she recently wrecked her car.”
“Although” is used to indicate the contrasting facts/events. On the one hand, Mary is a cautious driver. However, in conflict to this fact, she had a car accident.
The meaning that the original sentence in the problem is trying to convey is that seeing rainbows is not an easy thing to do EVEN THOUGH the circumstances that cause them are pretty common.
DESPITE the fact that the conditions they cause rainbows is common, it is difficult to actually see one. “Although” does not convey the same meaning as “even though”, “despite the fact,” or “though.”
Answer C uses the subordinate word “though”, correctly portraying the intended meaning.
Furthermore, “twin reflections” is a substitute phrase used to refer to “double rainbows” in order to avoid redundancy. Substituting the noun phrase “double rainbows” for “twin reflections” and then re-reading the sentence makes the meaning much clearer.
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