The teenagers desire to earn money for the shortest pleasures desperately,
what do you mean bu stating "the shortest pleasures" ? Why desperately ? it sounds a bit awkward
The reason is because
the reason for this is that
students under eighteen years old
students
who are under 18 years old
hazardous for them
hazardous to them
in terms of a sense of thriftiness.
thrift
duties
duty
They will become money-oriented.
this does not link with previous statements
It is also disturbing for students to work while studying
it interrupts students' studying
When they graduate school and obtain remarkable careers
graduate from schools/colleges
they can earn more valuable money in safer and more sustainable place
ways
Students ought to not hold jobs due to weak condition which will cause great harm to health.
not to
the weak condition
their health
their needless extravagant
extravagant is adjective
The world is made of full of diverse opinions because people from different walks of life may take different stances on this issue .
omit this sentence and replace by "in conclusion"
by the way, all your body paragraphs say about "part-time job" not "job" in general. it does not stick to your prompt at all