Put in a/an or the in these sentences where necessary.

1) Would you like apple?

2) How often do you go to dentist?

3) Could you close door, please?

4) I'm sorry. I didn't mean to do that. It was mistake

5) Excuse me, where is bus station, please?

6) I've got problem. Can you help me?

1) AN apple

2) to THE dentist

3) THE door

4) A mistake

5) THE bus station

6) A problem