The present continuous

http://www.perfect-english-grammar.com/present-continuous.html

http://www.perfect-english-grammar.com/present-continuous-use.html

http://www.englishpage.com/verbpage/types.html

http://www.perfect-english-grammar.com/present-continuous-exercise-3.html

http://www.perfect-english-grammar.com/present-continuous-exercise-4.html

http://www.perfect-english-grammar.com/present-continuous-exercise-5.html

http://www.perfect-english-grammar.com/present-continuous-exercise-6.html

http://www.perfect-english-grammar.com/present-continuous-exercise-7.html