a qui sont les livres? Ce sont les miennes. Why isn't it ces sont les miennes?

Question

Why isn't ces used in this reply - given that les livres is plural

Cécile Janty-Davies · Accepted Answer

Ruth,
Just to add to what has been said - I cannot find the particular example you quote in the lesson as the word 'livres' in the feminine form would indicate pound sterling currencies, and if it were books, it would be ----
Ce sont les miens = they are mine 
I find the example -
À qui sont ces balles ----> Ce sont les miennes.
But in both cases, as Maarten said, the plural of
c'est 
is
ce sont.
C'est, ce sont = this is, these are (French Demonstrative Pronouns)
Bonne Continuation !

Maarten Kamp · Answer

Ruth,

«ce sont» is the plural form of «c'est». «ce» used in this manner is an indefinite, invariable pronoun that is used mostly, but not exclusively, with «être» (instead of cela/ça).

Of course «ce» ( ce,cet,cette,ces ) can also be an adjective - «ces» is then the only plural form of the adjective, and is followed by a noun, not a verb. ‘ Ces ‘ is never a pronoun.

C'est, ce sont = this is, these are (demonstrative pronouns)

demonstrative-adjectives-ce-cet-cette-and-ces-mean-this-that-and-these-those

https://progress.lawlessfrench.com/questions/view/use-of-ce-and-ces

Chris Wirt · Answer

Just to add to Maarten's answer:Ces is a demonstrative pronoun and always followed by a noun. For example: Ces livres sont les miennes. -- These books are mine.On the other hand, in ce sont, ce is the subject and functions as a noun:Ce sont les miennes. -- They are mine.