Quote:
The growth of the railroads led to the abolition of local times, which was determined by when the sun reached the observer's meridian and differing from city to city, and to the establishment of regional times.
(A) which was determined by when the sun reached the observer's meridian and differing
(B) which was determined by when the sun reached the observer's meridian and which differed
(C) which were determined by when the sun reached the observer's meridian and differing
(D) determined by when the sun reached the observer's meridian and differed
(E) determined by when the sun reached the observer's meridian and differing
The growth of the railroads led to the abolition of local times, which was determined by when the sun reached the observer's meridian and differing from city to city, and to the establishment of regional times.
The choice above is wrong because the relative clause modifier that describes the local times has a passive voice verb (was determined) on one side of the parallelism marker 'and' but has a present participle (differing) on the other side. AS we know, a verb and a modifier do not go together. On the other hand, look at the correct choice E. The verb "was determined" has been replaced by a past participle (determined). Now, this choice is correct because there are two participles now on either side of the conjunction 'and'.
At the same time, look at choice D. Now you have 'determined' which is a past participle and modifier, while the word 'differed' is not a past participle but an active voice verb. Therefore, D is not parallel.
Let us come to brass-tacks about modifiers and their modifyees.
Also as we know that:
Theory - When we have an independent clause followed by a participle phrase, the participle phrase modifies the subject of the sentence. Then why not in the sentence at hand?
The critical question is, after the independent sentence, what kind of a participle phrase is following.
1. Is it a present participle modifier (Verb+ing) with a comma before?
Example: France won the 2018 FIFA World Cup, defeating Croatia 4-2.
Here defeating is adverbial modifying France's winning (not just France alone)
2. Is it a present participle without a comma before?
Example: The 2018 FIFA World Cup was a tame affair with France defeating Croatia 4-2.
Here the present participle is adjectival modifying the noun France, just before.
Takeaway: the present participle when separated by a comma need not modify the subject. It need not also modify the subject when not separated by a comma.
Let's now dissect past participles;
When a past participle (talked, frozen, eaten, kept, etc) follows an independent clause, it tends to modify the most logical noun despite its placement with a comma or without a comma.
Example:
In any language, idioms have to come to stay, perpetuated by centuries of traditions.
Here 'perpetuated' modifies the subject idioms because there is no other logical noun to modify before.
2. The Anasazi settlements at Chaco Canyon were built on a spectacular scale with more than 75 carefully engineered structures, of up to 600 rooms each, connected by a complex regional system of roads.
Here the past participle 'connected' does not modify the subject settlements, but modifies its nearest logical noun 'structures'.
Unless one builds up a thorough and full understanding, modifiers can be very tricky.
We must practice sentence patterns with various types of modifiers
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