Answer:
SA: At the store I bought an apple.
SB: That is a healthy choice, but I would have preferred some sweets.
SA: For dinner, I think I will have a hamburger.
SB: I will eat some pasta.
SA: I am thirsty. Can I have some orange juice?
SB: I had some chips, and they made me thirsty.
SA: I saw you drinking some tea.
SB: I want to eat a banana too.
SA: I will buy you one when I go to buy some coffee and some milk.
SB: I am also craving some chocolates.
SA: I am going to stop by the farmer's market and buy myself an apricot.
SB: I went last week to buy some eggs, and I tried a jacket potato.
SA: For dinner. I think I actually would like a hot dog.
SB: You better eat some grapes from the fridge too.
SA: I will. For breakfast I will have a biscuit, a peach, and some bacon.
I think the countable words are any with "a" or "an" in front of them, and the uncountable words have the word "some" in front.