In English, you must put an article in front of a noun - 'a', or 'the'. For example - a lesson, the student.
If the noun begins with a vowel, you write 'an', not 'a'. For example - an apple, an order.
If there is an adjective before the noun, you must also put an article. For example - an easy exercise.
If the noun is plural, you don't always put an article. For example - we like apples.
If there is a possessive adjective before the noun, you don't put an article. For example - my address
In this exercise, type 'a', 'an', 'the' in the box, or leave it blank.
Then check ANSWER