I have watched TV series Friends three times in one and half month. At the same time, I did not watch any TV or movie with Chinese language, and tried to avoid online Chinese language news. By the end of the month, I can catch most of the conversation without looking at the screen.
Friends is a powerful tool to improve listening and speaking skills, but individuals need to avoid the cultural pollution of the crappy American culture.
and I have no problem with TOEFL test and lectures.