That's good advice for someone learning a foreign language. What is your first language, then? How long have you been speaking English? (Your English is really good, by the way.)

I often ask questions just out of interest I also regard language as a kind of tool or toy - you've to work with it, test it, and also play with it --> esp. Puns! => trying to find out how to use it and how it works (for you). In my opinion,

Understandable. It never hurts to make sure. I commend you for asking a hypothetical question merely out of interest! I wish more people would do that.

Thanks very much, kitkattail. I place in, a passive like that sounded quite weird - but it could have been possible nevertheless so I just wanted to have a certainty.

You're right: it's the logical thing to assume. Unfortunately, languages aren't always logical. It makes sense, but that's just not the way it is. What you were taught is correct: there are no passives for these tenses.

I don't want to make them passive, I just wanted to know if there really is no passive form for those Perfect Progressive tenses while every other tense has a passive voice though. E.g. Present: "Tom writes a letter" --> "A letter is written by

No, the passive sentences are not correct. They cannot be used like that. Why would you want to make them passive? Isn't Tom more important than the letter? Why is the letter so important?

I've learned at school, that there's no passive for Perfect Progressive Tenses, is that true? Actually I wouldn't be surprised, if there is - so can I e.g. say "A letter has been being written by Tom" being passive of "Tom has been writing a

What are the differences between the present pefect simple and the present perfect progressive?