Could I ...?
Could I have some soda, please? --> No, sorry.
Could I ...?
Could I have some mushrooms and a cucumber? --> Sure./ Of course.
Could I ...?
Could I have some meat and some noodles, please? --> No, sorry.
Could I ....?
Could I have some rice, please? --> No, sorry.
Could I...?
Could I have some water, please? --> Sure./ Of course.
Could I ...?
Could I have some onions and a melon, please? --> Sure./ Of course.