Form 4

http://www.english-room.com/grammar/presentcontinuous_2.htm
https://www.englisch-hilfen.de/en/exercises/tenses/present_progressive_statements_contracted.htm
http://elovivo.com/introenglish/en/intro_english/lessons_wordlist/basic_english_lesson_14/lesson14b_ex.html
https://www.english-4u.de/en/tenses-exercises/present-simple-progressive4.htm
http://www.focus.olsztyn.pl/en-present-continuous-tense-exercises.html#.XHo3pogzZPY