Count / Non-Count, There is & There are

http://www.nonstopenglish.com/exercise.asp?exid=400

http://www.tcet.com/eaonline/GrammarCentral/thereis.html

http://www.members.iinet.net.au/~adelegc/grammar/there_is/thereis.html

http://www.english-room.com/read_6a.htm

http://english.baladre.org/sedaviwebfront/thereisare.htm

http://www.inglesmundial.com/I7/grammar.htm