Since then, I have found out that I have so many problems on pronunciation. For example: example, apple, build, invite, one, on, in, interest, down, call, will, shall, all, well, town, contest, fund,bad, happen,before, limitation.......... Sometimes, I even find 2-3 mistakes in one word. "apple" is one of good examples to show how we make 2 pronunciation mistakes in one simple word. I also realize that it is not easy to correct one's pronunciation. It is just more than difficult. Sometimes my tongue is even twisted. The reason for this is because we were taught in a wrong way and the tongue has already adapted that way. But after noticing these problems, I try hard to correct and I am improving my pronunciation slowly. I have not taken any courses at all. I think your own effort is more important than any courses.