classes:  lecturer. for groups to present to avoid the fact that you copy the article on the net and do not understand the article.  curriculum. for groups to present to avoid the fact that you copy the article on the net and do not understand the article.  facility. for groups to present to avoid the fact that you copy the article on the net and do not understand the article.  general. for groups to present to avoid the fact that you copy the article on the net and do not understand the article.