English connectors

http://www.shertonenglish.com/resources/es/connectors/connectors-functional.php
http://perso.wanadoo.es/autoenglish/gr.connect.i.htm
http://www.grammar-quizzes.com/9-10.html
http://www.polseguera.org/advanced_english_grammar/connectors.php (Grammar review)
http://www2.udec.cl/~ebanados/proyecto/rules.htm ( with charts)http://free-english-study.com/home/grammar-index.html