Question

I shall come back in --------- hour

Answer 1

I shall be back in an hour

Answer 2

I shall come back in an hour.

Explanation:

An article is a determiner that determines the quantity of a noun and gives a sense of definition to it. There are three main types of articles- a, an, and the. In this sentence, the word hour begins with an 'h' which is a consonant.

However, as 'h' is silent the pronunciation of this word is ‘our’ and 'o' is a vowel. So an is used before hour and not 'a'. If the h wasn’t silent then a 'would' have been used.