sentence structure

When you see seemingly unexplainable structures, such as this, in English, the reason is almost always that ellipsis (words have been eliminated and are understood from the context) has been used. Here the complete sentence would be something like: "Whereas the water of a stream flows as an unimpeded mass through an open channel, groundwater must move through small, constricted passages." Over

When you see seemingly unexplainable structures, such as this, in English, the reason is almost always that ellipsis (words have been eliminated and are understood from the context) has been used.

You are right about this but you have gone too far about this.
This is simple; the word 'unimpeded' is pseudo-complement and it modify the verb 'flows' and indicate

park sang joonYou are right about this, but you have gone too far. about this. This It is simple; the word 'unimpeded' is a pseudo-complement. and

moon7296the water of a stream flows unimpeded

The use of "unimpeded" here is sometimes called a secondary predication.

The water flows (First predicate)
The water is unimpeded. (Second predicate)

It's common for the second predicate to be somewhat like an adjective and somewhat like an adverb. Grammarians have been known to argue over wh

Thank you Mr.Jim for your proofreading.
I'm at a loss for words about these frequent mistakes.
Nonetheless, I'd like to ask

park sang joonI'd like to know why I can't use 'this' in place of 'it'.

I should have put it in blue instead of in red. (In my posts that often means that it's a suggestion, not an error.)

You just used 'this' in the previous sentence, so it sounded less than optimal to my ear to use 'this' again so soon.

This is purely stylistic, not gramma

Thank you, Mr.Jim for your careful concern which you have shown in proofreading my clumsy sentences.