Final answer:
The sentences should be completed with the appropriate articles 'the', 'a', or 'an' before nouns as needed to clarify the specificity and countability of the nouns in the sentences.
Step-by-step explanation:
To answer the student's question regarding the completion of sentences with the correct article, here is how they should be completed:
- California borders the Pacific Ocean.
 - I am a doctor.
 - An apple a day keeps the doctor away.
 - Have you been to the Arctic?
 - Cairo is the capital of Egypt.
 - It is a beautiful story.
 - It is an indication.
 - It breezed from the west all day.
 - What is an offer letter?