prepositions of time

Mark is arranging business meeting .

Mark :  I' m sorry I was out when you called (1) ... yesterday afternoon, Alice. Look, I'm free (2) ... the fifteenth of March.
Can we meet then?
Alice :  I'm pretty busy (3) ... next week, I'm afraid. I can't see you (4) ... Friday.
Mark :  I'd like to have a meeting (5) ... this month if possible. I'll be very busy (6) … April.
Alice :  I'm going away (7) ... Easter, so how about the week after? Shall we meet (8) ... the twenty-seventh? That's a Wednesday.
Mark : I've got an appointment (9) ... the morning but nothing (10) ... the afternoon. Let's meet (11) ... Wednesday afternoon
(12) ... half past two.