I'm not sure if this related but imagine nouns in English weren't marked for plurality:

one child->many child
one apple->two apple

1) The apple are good.
2) The apple is good.
3) Many apple are good.
4) One apple is good.

You then probably have to use quantifiers (one, many) or verbs (is, are) to indicate whether you mean a singular instance of the item or many instances.

Additional note:

OTOH, maybe there's some redundancy there. Because the verbs already tell you whether you're talking about a singular entity or a plural one (a case in point: The sheep is still alive vs The sheep are still alive.).

In Chinese, nouns themselves are not marked for plurality. Instead, quantifiers are used to do the job.