1)Are you coming to the party .... Saturday?
A. on B. at C. in
2) The .... is in the kitchen.
A. bathtub B. fridge C. bookcase
3) There is ... food in the cupboard
A. any B. a C. some
4) Could you go to the .. for some bread?
A. bake's B. butcher's C. chemist's 
5) Don't forget to put a ... on the envelope
A. letter B. mark C. stamp