Hi!
Have you got any problems with grammar? Don't worry and have a look these links where you can do lots of exercises. Here, you can improve present and past simple, present and past continuos and present and past perfect, too.
http://ies1libertas.edu.gva.es/departamentos/ingles/refeso4.html
http://www.autoenglish.org/repaso/4ESO.htm
http://www.burlingtonbooks.com/Spain/Page.aspx?PageID=409
http://www.ompersonal.com.ar/omexercise/contenidotematico.htm
http://mbonillo.xavierre.com/grammar/4eso.html
I hope that help you.
Kisses :)
