I worked for certain language centers in Vietnam. I am an English teacher.
Students coming to those center are quite "lazy". Most of them just learn in class and do not study or even do homework at home. So the question is that how they improve their language skill without practice? They just depend on 1.5 hour in class. of course it is not enough.
For some students, they have language ability, so they can have good result at the end of each English class. However, for others, when they have bad grades in the final exam, all the responsibilities to explain to their parents and to school's manager are belonged to English teacher. I worked so hard. But their parents are looking down on me due to something which is not coming from my side.