Why differed in D cannot act as a participle
Can we rule out D because local times are still differing
why "times, determined by" is not proper subject-verb config is not correct construction

how this is correct then

One of the earliest known birds with a beak and contour feathers, Confuciusornis sanctus,had large clawlike “thumbs” on its wings, probably to help it

one-of-the-earliest-known-birds-with-a-beak-and-contour-feat-t1946.html

"differed" is not a participle because it CAN'T be a participle. there is no such form.

only transitive verbs (i.e., verbs with DIRECT OBJECTS) can appear as the comma + past participle type of modifier.
this is true because this modifier is a passive voice form, and only verbs with objects can appear in the passive voice.

for instance:
"to throw" takes a direct object (i threw the ball).
therefore, it has passive forms (the ball was thrown).
therefore, it can appear in this sort of modifier (the ball, thrown by the pitcher, ...)

"differ" doesn't take a direct object, so it can't appear in the passive (e.g., it's impossible to say that something "is differed" or "was differed"). therefore, it can't appear as this sort of modifier, either.

Great explanation!

Can someone explain again why C is wrong? I still do not get the parallelism in C

Dear Ron,
I understood your point in the verb-ing example. Appreciate if you could answer my questions -

The growth led to X, which were A and B, and Y.

1. Can I have X and Y as -

X - which were determined by tests
Y - painted in blue color

Thus the complete sentence would be -

The growth led to X, which were determined by tests and painted in blue color, and Y

2. In the above sentence both X and Y are working verbs. X and Y are not participles because they are preceded by "were". Right ?

Appreciate you valuable help and time here.

regards,
Ankit

i think you're having some problems with your A/B/X/Y here -- i'm a little confused. it seems that the X and Y in your discussion are actually the A and B in your original sentence on top; correct me if i'm wrong.

what do you mean by "working verbs"? i'm not familiar with that terminology.

in any case, when you look at something like "were determined", you can look at this in two ways that are not really different:
1) it's a passive-voice verb
2) it's a form of "to be" (were) + a past participle (determined).
note that these are not different, because (2) is actually the definition of the passive voice: i.e., the passive voice is defined as a verb form of "to be" plus a past participle.

but, no, "determined" and "painted" are not themselves verbs in this case.

i can understand the confusion -- for these verbs, the participle and the past tense look identical (both are "determined").
for cases like these, here's a test:
if a form works like other past participles -- such as "driven", "given", "done", etc. -- then it's a participle.
if a form works like other past tense verbs -- such as "drove", "gave", "did", etc. -- then it's a participle.

here, "X were driven and given" would work, and "X were drove and gave" would be incorrect. therefore, these are participles, not past tense verbs.

Again great explanation Ron, you ROCK !!

My apologies for the confusion among x,y,a,and b, and for using a wrong term - working verbs. I meant "verbs".

About this problem, can I, in a nutshell, conclude -

1. Clearly determined is being used in all the options as a participle but not as a verb.
, which were determined by ..... (past participle)
, determined by .... (past participle)

2. Now to maintain the parallelism we need to have a participle form of the second verb.

3. After removing other errors, we are left with the below options -
(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

4. Option C is grammatically correct as both constructions are parallel -
which were determined by when the sun reached the observer’s meridian and differing
[past participle] ......... [present participle]

but the ONLY problem is -->
we use the construction 'were verbing' is limited to situations in which something else happened during the verb-ing.
example: while the man was chatting with his girlfriend, his cell phone broke the calm with its strident ringtone.

5. Option D is grammatically incorrect as there is no past participle of verb differ as differed, because differ is an intransitive verb

6. This leaves option E which removes the issue (were verbing) that was with option C and maintains parallelism.

=> Can you please confirm my understanding ?
=> Also is there any difference between "X which was driven by .." and "X, driven by ... " constructions. Or it merely depends on the context and how these constructions are used in a sentence.

Appreciate your patience while reading, interpreting and answering such questions from novices, such as me ( or I ? )

Regards,
Ankit Saxena

SC1000 is a banned source, so we will no longer add to this thread. one final comment:



an "-ing" MODIFIER is substantially more flexible than the VERB "is/are/was/were verbing".
for proof, see OG12 #42, which was presumably the inspiration for this problem.