Doing things changes things

I'm a sleeping guy, espcially in classes.
I am wondering that is it a physical or emotional problem?

"Sleeping Beauty" was a nickname given by my classmates in cram school.
I don't want to always doze off, because sleeping in class actually wastes my time.

This is a short-term training for emergency technism, and people who finish the 50 hours of lecture and pass a series of exams can have a license and have some ability to help people in need.
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Actually some lectures are boring because they are too simple for me and always Iet me doze off. However, there are still fun sometimes.
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It's time to cheer myself up!
I have already hated to repeat something over many years.
Though feeling sad, but I have to stand doing these studying.

I know that I will be a doctor and I can be a good doctor more than just a teacher.