Simple Present Tense: negative
Do/does: the third person singular changes from do to does; Verb: the base form of the verb is the same (without any changes);
Verb “to do” is an auxiliary verb
the other verb is the main verb
** Do/ Does/ Did + infinitive **
Simple Present Tense: affirmative / negative (contracted form)
Let's Practice Online
Negative
http://www.ego4u.com/en/cram-u[...]e-present/shortforms/exercises
Negative
http://www.ego4u.com/en/cram-u[...]resent/shortforms/exercises?02
Negative
http://www.ego4u.com/en/cram-u[...]mple-present/form/exercises?04
http://www.englisch-hilfen.de/[...]n/exercises/tenses/do_does.htm
http://www.englisch-hilfen.de/[...]/exercises/tenses/do_does2.htm
http://www.englisch-hilfen.de/en/exercises/tenses/do.htm
http://www.englisch-hilfen.de/[...]/exercises/tenses/do_does2.htm
http://www.englisch-hilfen.de/[...]n/exercises/tenses/do_does.htm
http://www.ego4u.com/en/cram-u[...]e-present/shortforms/exercises
Negative
http://www.ego4u.com/en/cram-u[...]resent/shortforms/exercises?02
Negative
http://www.ego4u.com/en/cram-u[...]mple-present/form/exercises?04
http://www.englisch-hilfen.de/[...]n/exercises/tenses/do_does.htm
http://www.englisch-hilfen.de/[...]/exercises/tenses/do_does2.htm
http://www.englisch-hilfen.de/en/exercises/tenses/do.htm
http://www.englisch-hilfen.de/[...]/exercises/tenses/do_does2.htm
http://www.englisch-hilfen.de/[...]n/exercises/tenses/do_does.htm