I encounter this expressions that stand for physical entities. But for example, speed is not a thing, it is a property that a thing can have, so how can a car be a great speed? I'm looking for grammatical insights and justifications.
This concession is not a public information.
This car is a great speed.
This book is a long read.
The quiz is a multiple choice.
Best Answer
This concession is not a public information. - Is inaccurate as the definition of "concession" in the sentence would not be a public agreement. Therefore it doesn't require the article "a" to modify it.
This car is a great speed. - Is grammatically incorrect. The "car" is a noun that cannot be grammatically modified by the word "speed." The sentence is poorly formed and it would require complete restructuring to make sense.
This book is a long read. This sentence is grammatically correct. "Read" modifies the noun book and long is at the correct adjective for this sentence.
The quiz is a multiple choice. Is grammatically incorrect. There is no need for the article "a" to modify "multiple choice". The correct sentence would read: The quiz is multiple choice."