The site is also intended as a free extra aid to teachers. There are many materials here which can work well in the classroom (or for students' homework). Why the focus on grammar? Because it's basic grammar mistakes that sound the worst to native speakers - and often all that's needed is a little more understanding and practice. As we continue to add lessons and exercises, we strongly recommend that students keep coming back and reviewing old lessons until individual grammar points are automatic. Why do we offer the materials for free? We are able to keep our materials free by running occasional advertising and offering certain paid materials, which help pay for the running costs of the site.