Put in the or a/an.1) What it ..... longest river in

Put in the or a/an.

1) What it ..... longest river in the world?
2) Yesterday I bought .... newspaper and .... magazine. ..... newspaper was very interesting. .... magazine was boring.
3) Would you like .... apple?
4) We had dinner in ..... very nice cafe.
5) I often listen to ..... radio.
6) Jill played ..... violin in an orchestra.