1. There is a box of apples.

2. There is a bunch of bananas.
3. There are two baskets of oranges.
4. There are a few cartons of milk on the table.
5. There is a bunch of grapes in the box.
6. There are two bunches of grapes in the paper box.

(Are the expressions all grammatical?)

All are fine!! Congrats! =)

To determine if the expressions are grammatical, we need to analyze each one individually.

1. "There is a box of apples." - This expression is grammatically correct as it follows the pattern of "There is/are + noun phrase." In this case, the noun phrase is "a box of apples."

2. "There is a bunch of bananas." - This expression is also grammatically correct. It follows the same pattern as the previous one, with the noun phrase being "a bunch of bananas."

3. "There are two baskets of oranges." - This expression is grammatically correct as well. It follows the pattern for plural nouns, using "are" instead of "is."

4. "There are a few cartons of milk on the table." - This expression is grammatically correct because it uses the plural form "are" to match the noun phrase "a few cartons of milk."

5. "There is a bunch of grapes in the box." - This expression is grammatically correct, following the same pattern as the previous ones.

6. "There are two bunches of grapes in the paper box." - This expression is also grammatically correct, as it uses the plural form "are" to match the noun phrase "two bunches of grapes."

In summary, all of the expressions given are grammatically correct as they follow the appropriate patterns for singular and plural nouns in sentences using "There is/are."