Is my grammar correct in this sentence?

[bbmak]

Is my grammar correct in this sentence? If there are ways to make the sentence more smooth please help me to rephrase or reword the sentence.

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Not many instructors are willing to put up extra time to tutor their students because the extra time that they devote to student is considered as volunteer works, in other word none paid job.
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[Mister Micawber]

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Not many instructors are willing to put in extra time to tutor their students, because that time is considered to be volunteered-- in other words, unpaid overtime.
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