add "a" or "an"

1: _____cat
2:_____baby
3:_____armchair
4:_____iron
5:_____lion
6:____ dog
7:____fish
8:___ eye
9:____ car
10:____tree
11:___ duck
12:____ lemon
13:____ear
14:____octopus
15:____ eagle
me ayudan ​