If you were not a banker, what would you do?
If I were not a banker, I would be a musical composer

Which name is located in front of a sentence, between first name and last name in Korea?
Last name is located in front of a sentence in Korea

***************Correction for Jerome's Homework********

If you were not a banker, what would you do?
If I were not a banker, I would be a musical composer

Which name is located in front of a sentence, between first name and last name in Korea?
Last name is located in front of a sentence in Korea

Jerome: If you were not a banker
Correct: If you are not a banker

Explanation:
Let us the be verb "are" to indicate that you're asked about your current job.

Jerome: If I were not a banker
Correct: If I am not a banker

Explanation:
Let us use the be verb "am" to indicate that you talk about your current job position.

Jerome: I would be a musical composer
Correct: I would be a musical composer.

Explanation:
Let us not forget to use the right punctuation mark when we end our sentence. Let us put period (.) to end your sentence.

Jerome: front of a sentence
Correct: beginning of a sentence

Explanation:
It is better to use the word "beginning" to express the location of a certain word in a sentence.

Jerome: Last name is located in front of a sentence in Korea
Correct: In Korea, the last name is placed before the first name.

Explanation:
Let us express your sentence that way for it to be clearly understood.

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Hi Jerome! Thank you for sending your composition today. I am very glad with how eager you are to express clearly your thoughts and ideas that are related to our lesson. I gave a little corrections to help you express it more better. Please take note of it. Keep up the good work! ^_^