There is ... milk.
some
There isn't ... sugar.
any
There isn't ... water in a glass.
any
There is ... apple
an
There aren't ... biscuits.
any
There is ... egg.
an
There's ... big, chocolate cake.
a
I haven't got ... apples.
any
There is ... cheese.
some
Have we got ... bread?
any
Would you like ... lemonade?
some
This is ... orange.
an
There are ... potatoes.
lots of/ a lot of
There are ... eggs.
lots of/ a lot of
There's ... butter on the bread.
some