Resposta:

a.. a .. book

b... an . exam

c.... an . engineer

d.... a . teacher

e.....an english book

f..... a  car

g.....  a jacket

h..... an elephant

e.....  a movie

J..... an octopus

k.... a dictionary

l.... an air plane

m.... a board

n.... a nose ​

Explicação:

an = before vowel sounds and a = before consonant sounds

we can use the definite article THE for all those nouns since it is used for countable and uncountable nouns, however the person is specifying the noun or already know it