Question

it is an useful article spot the error​

Answer 1

Answer:

Although 'useful' begins with the letter 'u', its pronunciation begins with a Y-sound which is a consonant sound. Therefore the article used must be 'a' and not 'an'. The correct sentence is-

The telephone is a useful instrument.

Answer 2

Answer:

Although 'useful' begins with the letter 'u', its pronunciation begins with a Y-sound which is a consonant sound. Therefore the article used must be 'a' and not 'an'. The correct sentence is-

The telephone is a useful instrument.