Why masculine singular, not plural?

Question

I took a test with this sentence where I fill in the blank with drop down. I chose Bonnes and realize it is wrong due to using the masculine form after C'est. However, isn't 'apples' plural? Why is it bon and not bons?
- Cette pomme est bonne. - Oui, c'est ________, les pommes ! This apple is good. - Yes, apples are good!

Maarten Kamp · Answer

Carole,

In simple descriptive statements with stand-alone adjectives (which could be an adjective modified by an adverb), it is always ‘ c’est’ that is used.

‘Ce sont ‘ , the plural form, is never used in this context.

‘ C’est ‘ is always singular and masculine grammatically, so the adjective will always be in masculine singular form when it is stand alone and not directly modifying a noun.

There are other nuances of usage in everyday French as well.

See attached lesson for further discussion :

C'est, ce sont = this is, these are (French Demonstrative Pronouns)