What is the Classical Chinese character for "about"?

In "Du's Handbook of Classical Chinese Grammar," the following Chinese sentence and English translation appear, except without the Korean pronunciations:

子(자)何(하)不(불)告(고)以(이)所(소)往(왕)?

Why will you not tell me where he has gone?

I mentioned in a previous post HERE that I am suspicious of 以 (이) being used simply as a direct object marker with only certain transitive verbs that can have both direct and indirect objects. Why not all transitive verbs that can have direct and indirect objects? "Du's Handbook" says that the verbs with which 以 is used in such a way are typically those with the meanings of "giving," "telling," and "teaching." In the cases of "telling" and "teaching," however, it seems that 以 could be translated as "about," which seems like a better way of dealing with it than simply calling it "a marker." Besides, one could argue that "about" is also a direct object marker.

In the above example, "Du's Handbook" seems to have used 以 (이) as a direct object marker for the phrase "where he has gone" (所往). Instead, consider the following translation:

子(자)何(하)不(불)告(고)以(이)所(소)往(왕)?

You (子), why (何) not (不) tell (告) about (以) the place (所) [he] has gone (往)?

And here is the example from my previous posting:

敎(교)其(기)子(자)以(이)齊(제)語(어)

Taught (敎) his (其) son (子) about (以) the Qí (齊) language (語).

Here is another example:

敎(교)人(인)以(이)善(선)

Teaching (敎) people (人) about (以) goodness (善).

Since 以 (이) has been used in such situations as a direct object marker, I see no harm in translating it as "about" since "about" also essentially serves as a direct object marker. With a character meaning "to give," however, a separate translation is  required.

With a verb meaning "to give," 以 (이) could be translated as "to take," which in Korean is 가지다. Consider the following Chinese sentence examples from "Du's Handbook," even though the Handbook translated them differently than the way they are translated below:

王(왕)以(이)千(천)金(금)賜(사)功(공)臣(신)

The king (王) took (以) one thousand (千) [pieces of] gold (金) [and] bestowed [them] on (賜) the meritorious (功) minister (臣).

乃(내)以(이)半(반)價(가)返(반)之(지)

Then (乃) took (以) half (半) the cost (價) [and] returned [it] (返) [to] him (之).

Can anyone think of any examples where the above translations would not work? By the way, there is nothing really wrong with translating 以 (이) as a direct object marker in the above cases, especially since the Korean language has its own direct object marker in the form of 을/를.