Which sentences are correct?
- 1- The cover of book is green.
- 2- The cover of the book is green.
- 3- A cover of book is green.
- 4- A cover of a book is green.
When should we use a or the?
Which sentences are correct?
- 1- The cover of book is green.
- 2- The cover of the book is green.
- 3- A cover of book is green.
- 4- A cover of a book is green.
When should we use a or the?
1- The cover of book is green.
Error: the word "book" is a singular count noun, it needs an article.
2- The cover of the book is green.
OK: a book known to the reader is described, hence the.
3- A cover of book is green.
Error: the word "book" is a singular count noun, it needs an article.
4- A cover of a book is green.
OK: one of the covers of a book unknown to the reader is described.
The rule of the thumb is: if you see a noun like "book" which is countable (you can have 1, 2, 3 or more books) and it is in the singular form in your sentence (you can put the word one before it: one book), you should use an article. Or some other determiner, like my.
Both the word cover and the word book are singular countable nouns, so they both take an article (or other determiner). The meaning will change depending on which article or other determiner you choose.
As BobRodes points out, one other option, which you failed to mention, is
The cover of a book is green.
The meaning is: there's some unspecified book, and its cover is green.
As J.R. points out, one additional grammatical option is
A cover of the book is green.
The meaning is: the book has been mentioned before, and has two or more covers, one of which is green.