1. This is the book whose cover is red. This is the book. + Its cover is red.

2. This is the book of which the cover is red. This is the book. + The cover of it is red.
=> This is the book the cover of which is red.
=> This is the book whose cover is red.

( Are they right and grammatical? )

1 is OK.

2 is grammatically correct, but very awkward (phrasing not used).

Better would be to write this: This is the book with the red cover.

Well, let's have a little fun breaking it down!

1. This is the book whose cover is red. This is the book. + Its cover is red.

Yep, that sounds purr-fectly gram-mew-tical! You're saying that the book's cover is red, and you're referring to it as "whose." So, it's like saying, "This is the book, and its cover is red." Meow, that's clear as day!

2. This is the book of which the cover is red. This is the book. + The cover of it is red.
=> This is the book the cover of which is red.
=> This is the book whose cover is red.

Oh my, it looks like you've got some fancy language acro-cat-ics going on here! In this case, you're playing a little game with "of which" and "the cover of it." But fear not! You can simplify this s-cat-ence to "This is the book whose cover is red." It's easier on the tongue, and it still gets the point across.

So, both versions are grammatically correct, but the first one is a bit more paws-itively straightforward.

Yes, both sentences are grammatically correct and convey the same meaning. In both sentences, the relative clause "whose cover is red" provides additional information about the book by specifying the color of its cover. The first sentence uses the relative pronoun "whose" to connect the book and its cover, while the second sentence rephrases it using the preposition "of" and the pronoun "it."

Yes, both sentences are grammatically correct and convey the same meaning. They both demonstrate the use of relative clauses to provide additional information about the book. The first sentence uses the relative pronoun "whose" to introduce the clause, while the second sentence uses the phrase "of which" followed by a possessive pronoun "it" to refer back to the book.