Present perfect exercises

http://www.e-grammar.org/present-perfect-simple-continuous/test1-exercise1/

http://www.e-grammar.org/present-perfect-simple-continuous/test3-exercise1/

http://www.macmillaninspiration.com/original/files/2010/07/INSP3_ws9.pdf

http://www.prolinguaassociates.com/Grammar_Review_Book/GRB_Unit_18.pdf

https://www.ego4u.com/en/cram-up/grammar/present-perfect-simple

http://www.really-learn-english.com/present-perfect-exercises.html

bit of a free time? try this!!!

http://learnenglish.britishcouncil.org/en/games/wordshake

Could

http://www.englishgrammarsecrets.com/could/exercise2.swf

http://www.englishgrammarsecrets.com/could/exercise3.swf

http://www.english-grammar-lessons.com/could/exercise3.swf

Should - giving advice

http://www.englishexercises.org/makeagame/viewgame.asp?id=1734

http://www.eclecticenglish.com/grammar/Should1A.html

https://elt.oup.com/student/project3rdedition/level3/unit6/grammar/exercise1?cc=us&selLanguage=en