Be to

I cannot analyze your problem because you have not put the phrases into representative sentences.

There are no representative sentences simply because that person has made such a general statement as above without any examples; he seems to be saying that in general "how to do/what to do…" are equal to "how X to do/what X is to do..."

Well, if you want examples, what about these simple ones?

·He knows how to do it.
·He knows how he is to do it.

To m

Taka·He knows how to do it.·He knows how he is to do it.To me, they don't seem the same at all.

Nor to me. Is that all there is to your question, then?

I just wondered if that generalization was really valid or not.

And that person has also made this formula: "prep+relative pronoun+to do=prep+relative pronoun+ X is to do"

I wonder if these two are really the same:

I need something with which to write.
I need something with which I am to write.

TakaI wonder if these two are really the same:I need something with which to write.I need something with which I am to write.

I can't see how, since it can also mean 'with which she/he/my student/etc is to write'. But if X refers to anyone, then that is a fair paraphrase, I suppose.

Mister Micawber . But if X refers to anyone, then that is a fair paraphrase, I suppose.

Would you come up with an example where, like the first how-to-do example, such a conversion wouldn't work? Or do you think his formula generally applies?

I don't know about 'conversion'; it is just a paraphrase to me.

Then, any example that shows such paraphrasing wouldn't work?

So,what's the difference in meaning?
Cuz it seems the same meaning in my languge
He knows how to do it.
He knows how he is to do it.