Various Crossword Questions

[Billy_Bonka]

1- Ancient Greek building for music (5) O?E?N
2-Dad's to ring short mathematician (6) ????A?
3- It helps writer make a point (6-9) ??N?I? / ??A?V?N?? 4- Fantastic sea snail on top of terrapin swimming around (11) ??N?A?????T
5- Damage before a short fight gets you the bird (7)
??D?B??
6- Composure required as I sit for artist outside (5) I?I?? 7- Nothing to tease if receding for hairdresser (6)
?I?A?O
8- 8s, Spooner's drawing paper (6,5) R?W?N? / T?A?S 9- First of athletes stepped into some sports arena (9) ??B?O?O?E
10- Hearing having apprehended officer - here? (5,7) Court/ ???T???
11-Dark horse that may be last in Derby, literally (7,8) Unknown / ?U???I??
12- Starts to ask for part of test (10) ?????N???S
13- Hurried outside to set out a spread (7) ??L???D

Thanks in advance.

[ace bt]

1 odeon
3 pencil sharpener
5 marabou
8 rowing teams
9 astro dome
10 court martial

[sohcahtoa]

2 Pascal

[ace bt]

7 figaro

[ace bt]

4 sensational (anagram)

[tyrepill]

11 Unknown quantity

[ace bt]

6 poise

[tyrepill]

12 Beginnings

[alcibiades]

12. Beginnings 13 Splayed

[hammersgirl]

13 splayed

[Billy_Bonka]

Thanks Folks.