There is [a/an] apple.
There is an apple.
There is a orange.
There is an orange.
There is [a/an] pit in the avocado.
There is a pit in the avocado.
There aren't some strawberries in the garden.
There aren't any strawberries in the garden.
There isn't [a/an] fruit salad on the table.
There isn't a fruit salad on the table.
There is a apple and an banana in your lunch bag.
There is an apple and a banana in your lunch bag.
There is [a/an] bag of grapes in the fridge.
There is a bag of grapes in the fridge.
There aren't some orange trees at the apple orchard, but there are any apple trees.
There aren't any orange trees at the apple orchard, but there are some apple trees.
There is [a/an] orange and [a/an] carrot in my juice.
There is an orange and a carrot in my juice.
Is there an pit in the avocado?
Yes, there aren't any.
Is there a pit in the avocado?
Yes, there is.