Though I’m not very fluent in english
Yes you are. Your english isn't perfect, but it's better than most filipinos, and some native speakers, when it comes to writing.
I believed that there’s no dumb student, it’s just a matter of choosing between being lazy or being industrious.
There are dumb people. The majority of students are likely average though, and they often can still do well in school. There are even smart kids that don't do that well. Sure, sometimes they're lazy. Often there's a reason though.
It is the teacher's job to teach, and the student's job to learn. When the student isn't doing their job, it is both the student and the teacher's failing.
Welcome to steemit. Hope you do well here.