Hello!
I'm reading a book about construction grammar. There is an example sentence in the book: There was cat all over the road.
The book says this is a tragic story (a cat was dead), which makes me a little confused. Because according to my knowledge, the more acceptable sentence is "There were cats all over the road". However, this sentence has nothing to do with one pathetic cat.
So my questions are:
① Why does this sentence mean the cat was dead ?
② If it does have a special meaning, Is this a generally accepted expression or just a temporary art of speech? (Because this sentence would be considered grammatically incorrect in English learning.)

Thanks a lot!

Question

Hello! 
  I'm reading a book about construction grammar. There is an example sentence in the book: There was cat all over the road. 
  The book says this is a tragic story (a cat was dead), which makes me a little confused. Because according to my knowledge, the more acceptable sentence is "There were cats all over the road". However, this sentence has nothing to do with one pathetic cat.
  So my questions are:  
① Why does this sentence mean the cat was dead ?
② If it does have a special meaning, Is this a generally accepted expression or just a temporary art of speech? (Because this sentence would be considered grammatically incorrect in English learning.)

Thanks a lot!

Answer

The idea is that one cat has had its flesh and bones spread far and wide across the road surface. It's not a common expression at all, but rather a writer being uniquely creative.

Answer

You could think of it like this. . . The cat was destroyed so completely that the word CAT no longer refers to the animal, but to the substance CAT.   Just like saying there was mud or water all over the road.

Answer

In addition:

"There was cake all over his face." - Meaning, he is a messy eater and the food is on his face still after eating his cake.

"There was cat all over the road." - There are bits of cat body (one cat or multiple) all over the road. Cat is being used more as an object rather than a living subject or animal.

Answer

(1) Why does this sentence mean the cat was dead ?
In my opinion, "there was cat all over the road" meant it was scanned by many cars just go through the cats and they're basically dead.
(2) You think that the grammar is accepted "There were cats all over the road" but I think "There were cats all over the road" represents that the cats are on the road (not dead) and "there was cat all over the road" mean that they're dead and their body are splitting out everywhere, bloody (I'm not trying to be creepy) so yeah, it was my opinion if I don't trust me it's fine. Best of luck to you