Вставьте пожалуйста определённый\неопределённый артикль где это необходимо: 1) I usually eat .... sandwiches or ....

1) I usually eat sandwiches or a humburger. 2) Are there any books in the box? 3) Mike is an engineer. 4) Would you prefer an apple or an orange. 5) Give me a sheet of paper. 6) I met the man you were talking about over telephone yesterday. 7) We studied the history of music and architecture. 8) At concert Jane was playing the violin. 9) The Smiths sent us the invitation to the house party they were giving on Saturday.