The following sentence has been split into four segments. Identify the segment that contains a grammatical error.

You should / see a oculist; / your eyes look / worse today.

The correct answer is 'see a oculist'.

Key Points

• The mistake in the sentence lies in the segment "see a oculist;" where the indefinite article "a" is used incorrectly before a vowel sound.
• The correct indefinite article to use before a word that starts with a vowel sound is "an," not "a."
• So, the corrected segment should be "see an oculist;" to properly align with the rules of English grammar regarding the usage of articles.

​Therefore, the correct sentence is: "You should see an oculist; your eyes look worse today."

Additional Information

• "A" is used before words that begin with a consonant sound, while "an" is used before words that begin with a vowel sound.
• This rule is based on sound, not spelling, so the use of "a" or "an" is determined by the pronunciation of the word that follows it.
• For example, we say "a university" (because 'university' begins with a 'yoo' sound, which is a consonant sound) and "an hour" (because 'hour' starts with a silent 'h' and therefore the first sound is 'ow', which is a vowel sound).