In Present tenses^x, Difference between^x, Perfect progressive^x

Present Perfect is formed with the auxiliary have and the past participle of some verb: have seen, has done, have lived. Present Perfect Progressive is formed with the auxiliaries have and been and the present participle of some verb: have been seeing, has been doing, has been living.CJ

Hi everyone,I have a few grammar questions and I don't know how to answer them:Explain why the verb “To Be” is not a non-progressive verb?I know the simple present never talks about the present but what can be an exception to this rule?Why does the present tense not exist in English? What...