Question

Write the rules of formation of following tenses
1. Present continuous
2.Present perfect
3. Present perfect continuous

Answer 1

1 - jin sentence ke last me rha h, rhi h, rhe h, baitha h, baithi h, leta h, leti h, aadi words aaye aese sentence ko present continuous tense khte h...
Helping Verb - is, am,are
Main Verb - ing form...

2- jin sentence ke last me chuka h, chuki h, chuke h, aadi words aaye aese sentence ko present Perfect tense khte h
Helping Verb - Has, Have
Main Verb - IIIrd form
3- jin sentence ke last me rha h, rhi h, rhe h, aadi words aaye aur work ke jari rhne ke sath time diya gya ho aese sentence ko present continuous tense khte h.
Helping Verb - has been, have been
Main Verb - ing form.

Answer 2

present continuous -subject +is/am/are+verb 1 form +ing + object .
present perfect -subject + has /have + verb 3 form .
present perfect continuous -subject + has /have +been +verb 1 form +ing + object .