Practice with irregular verbs: http://personal.colby.edu/~bknelson/SLC/presente_stem_change.php
more irregular verb practice (skip the ones you don't recognize): http://personal.colby.edu/~bknelson/SLC/presente1.php
Practice with -AR verbs: http://personal.colby.edu/~bknelson/SLC/presente_ar.php
Practice with -ER, -IR, ir, salir and hacer: http://personal.colby.edu/~bknelson/SLC/presente_er_ir.php
