Will vs Going to
https://elt.oup.com/student/solutions/preint/grammar/grammar_06_012e?cc=ar&selLanguage=en
http://www.better-english.com/grammar/willgo.htm
http://www.englisch-hilfen.de/en/exercises/tenses/will_going_to_future.htm
http://www.englishpage.com/verbpage/verbs18.htm
Simple past or past continuous
https://www.ego4u.com/en/cram-up/grammar/simpas-paspro/exercises?ex07
http://www.englisch-hilfen.de/en/exercises/tenses/simple_past_progressive.htm
https://www.ego4u.com/en/cram-up/grammar/simpas-paspro/exercises?ex06
https://www.ego4u.com/en/cram-up/grammar/simpas-paspro/exercises?ex05
https://www.ego4u.com/en/cram-up/grammar/simpas-paspro/exercises?ex04
https://www.ego4u.com/en/cram-up/grammar/simpas-paspro/exercises?ex03
https://www.ego4u.com/en/cram-up/grammar/simpas-paspro/exercises?ex02
https://www.ego4u.com/en/cram-up/grammar/simpas-paspro/exercises
Simple present vs present continuous
https://www.ego4u.com/en/cram-up/grammar/simpre-prepro/exercises?ex12
https://www.ego4u.com/en/cram-up/grammar/simpre-prepro/exercises?ex11
https://www.ego4u.com/en/cram-up/grammar/simpre-prepro/exercises?ex10
https://www.ego4u.com/en/cram-up/grammar/simpre-prepro/exercises?ex09
Some theory
https://www.ego4u.com/en/cram-up/grammar/simpre-prepro
