A Myth in learning English

Fast improvement in a short period of time
For example, many hakwons have advertisements that says
"TOEIC 900 in 3 months"
and in the advertisements are students who have actually succeeded in scoring 900 in TOEIC, and they say how much they have improved in this hakwon.

However, these succeeded students are probably ones who have already skills and are better than most.
Also, students need motivation in learning a foreign language. Hakwons can help students to have interest in learning English, but if the students have no interest at all, then there is no help hakwon can do because hawons do not care if the students do not come to class (not strict like school).