There is and there are exercises

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http://www.agendaweb.org/exercises/grammar/there-is-there-are.htm
http://www.englisch-hilfen.de/en/exercises/various/there_is_there_are3.htm
http://www.englisch-hilfen.de/en/exercises/various/there_is_there_are2.htm
http://www.englisch-hilfen.de/en/exercises/various/there_is_there_are4.htm