I would be very grateful for your help to understand the usage of "was" and "were" in this context.
There wan't any water left in the bottle.
There weren't any water left in the bottle.
There wasn't any apple left in the basket.
There weren't any apples left in the basket.
There were three apples left in the basket.
There was only one apple in the basket.
There was some water in the bottle.
But when it comes to deciding between "wasn't any" and "weren't any" I am confused as to which one to choose.
The simple answer to your other confusion is that you use "wasn't any" with uncountable nouns and "weren't any" with countable nouns.
There wasn't any water in the bowl.
There wasn't any sand on the beach.
There weren't any apples in the bowl.
There weren't any tourists on the beach.
The appropriate questions leading to those answers would be:
How much water was in the bowl?
How much sand was on the beach?
How many apples were in the bowl?
How many tourists were on the beach?
Uncountable nouns take the singular form and countable nouns take the plural in the interrogative and negative.
Thank you very much. Now it makes sense.