In which, of which and sentential clause

[ehimeme]

Hi Ron,

Can you please explain the usage of in which and of which?? Are they always preceded by a comma??

I dont really understand the sentential clause i.e when a clause modifies or refers to an entire preceding clause. Can you please explain with good examples??

Thanks,

[esledge]

Can you please explain the usage of in which and of which?? Are they always preceded by a comma??

in which, of which, on which, by which, over which, ....

The choice of preposition depends on the context, and is somewhat idiomatic. Commas? It depends on whether the modifying phrase is essential or inessential.

Without comma (essential modifiers):
The movie John Wayne starred in ... can be expressed The movie in which John Wayne starred...
The bridge we traveled over ... can be expressed The bridge over which we traveled...
The means by which a crime was committed are considered during the trial.

With comma (inessential modifiers):
Hard work, for which there is no substitution, will be rewarded on the GMAT.
My home office, in which I do most of my work, is noisy.

I dont really understand the sentential clause i.e when a clause modifies or refers to an entire preceding clause. Can you please explain with good examples??

I think this is an example of what you are talking about:
The cats sleep in the sun, stretching periodically and twitching as they dream.

The phrase after the comma describes several things at once:
How did the cats sleep? (i.e. it modifies the verb of the preceding clause)
Who was stretching and twitching? The cats! (i.e. it modifies the subject)

It's probably most complete to say that the modifier describes the whole main clause of the sentence, because both the subject and verb are correctly described by the modifier.

[ehimeme]

Thanks very much Emily for your response. I am very grateful.

[JonathanSchneider]

: )