21. He has been watching TV since morning. (Present Perfect Continuous.)
22. Tomorrow I am having an English class at 8 o'clock.(Present Continuous)
23. The air in the city is becoming more and more polluted. (Present Continuous)
24. I've lost my purse. (Present Perfect)
25. Her hair is dirty. She has been painting the house the whole day long.
(Present Perfect Continuous.)
26. You are always losing something! (Present Continuous)
27. You have already been writing the composition for two hours. (Present Perfect Continuous).
1 finishes,
are playing
2 are singing,
starts
3 is,
am staying
4 is seeing,
is
5 Is Josh working,
starts
Когда речь о расписании/графике, то используем Present Simple.
А если в предложении говорится о договоренности, запланированном действии, то используется Present Continuous.