Before you practise conditional sentences, you might want to have a quick revision. If you think you need it, please watch the following presentation.
http://www.slideworld.com/slideshow.aspx/conditional-sentences-ppt-2765988
Are you ready now? Click on the following link and do the following exercises: conditional sentences, statements and negations.
http://www.englisch-hilfen.de/en/exercises_list/if.htm
