Exercise 5. Write a, an.1 a …… book. 7 ……….. organization 13 …………. question2 an… old book 8 ……….. restaurant 14 …….important question3 …….. window 9 ……….. Chinese restaurant 15 ……….. hamburger 4 ……… horse 10 ……. Indian restaurant 16 ………. hour5 …….. airport 11 ……….. accident 17 ……….. economic problem6 ………university 12 ………bad accident 18 ……….nice evening