1. Вставь: a or an. 1atlas 2 pen 3..timetable 4apple

1. an atlas 2. a pen 3. a timetable 4. an apple 5. a school 6. an orange.

A / an is indefinite article. We use indefinite article with singular and we dont use indefinite article with plural. The meaning of indefinite article is one. A is used before consonants and an is used before vowels.