http://s.mound.free.fr/skyblues67/simplepresent/conj4frms/conjworkspres.htm
https://www.ego4u.com/en/cram-up/tests/simple-present-1
aff
https://agendaweb.org/verbs/present-simple/index.html
https://agendaweb.org/exercises/verbs/present-simple.htm
https://agendaweb.org/exercises/verbs/present-forms.htm
http://www.eflnet.com/grammar/presentagreement.php
int
http://www.grammar.cl/Games/Dont_Doesnt.htm
https://www.montsemorales.com/gramatica/PresSimpNeg1Spt.htm
http://www2.arnes.si/~oskplucija4/ces/psnegative.htm
http://www.bastrimbos.com/Hotpotatoesfiles/spresontk1.htm
https://www.englisch-hilfen.de/en/exercises/tenses/simple_present_negation_sentences.htm
neg
https://agendaweb.org/exercises/verbs/do-does
http://www.english-room.com/dodoes_5.htm
http://www.grammar.cl/Games/Short_Answers_Present.htm
http://www.englishexercises.org/makeagame/viewgame.asp?id=1277
http://www.bastrimbos.com/Hotpotatoesfiles/spresvraag2.htm
mix
https://www.montsemorales.com/gramatica/PresSimpQuesSw1-3.htm
http://www.perfect-english-grammar.com/present-simple-exercise-6.html
