Complex Sentences
Watch for information about Subordinating Conjunctions!
For now, see this very helpful site:
http://englishplus.com/grammar/00000377.htm
Here's another site about sentence patterns:
http://www.unc.edu/depts/wcweb/handouts/sentencepatterns.html
And this site offers games and activities:
http://www.bbc.co.uk/skillswise/words/grammar/sentencebasics/whatisasentence/