My teacher told me that it should be like "two cups of coffee is too much" and I wonder if it applies here? I understand it's common to say "there're too many books" and "there are enough cats". so my question is : are "books are too many" and "cats are not enough" correct to say? and what should I say if i put "many” and "enough" at the end of sentence.
These sentences are good:
Two cups of coffee is too much.
One cup of coffee is too much.
You can't really say these:
Cup of coffee is too much. [bad]
Cups of coffee is too much. [bad]
Likewise, you cannot say these sentences:
Books are too many. [bad]
Cats are not enough. [bad]
You can use this construction if you specify a quantity for the subject of each sentence. For example, these are all good:
A thousand books is too many.
One book is too many.
A dozen cats is not enough.
Zero cats is not enough.