The first reason is about students. Most of Thai students don't pay enough attention in the class. For example, there are 40 students in the class over 25 students always talking all the time in the class and some students will spend their privacy time in the class such as listening to music, drawing, and sleeping. And when their teacher assign them to do some homework they won't finish at home.There are a few students will listen what their teacher teach and intend study, so that will lead student who don't intend in the class to fail in the test and get a low grade in the end of semester.