Prepositions - In, At and On

Hi there
Guys, in this video class I explain in matters of time and location where we use In, At and On.
Well I hope you can enjoy this class and if you have any comments, suggestions u can write me.

Ola a todos
Nessa aula eu explico como se usa as Preposições In, At e On para expressar tempo e lugar
Alunos brasileiros, podem me escrever em português
http://www.youtube.com/watch?v=fhh4rLIGmwU


Exercise: http://personales.ya.com/mjandres/archivos/timeprep1.>
http://www.oup.com/elt/global/products/englishfile/elementary/a_grammar/file03/grammar03_d01/