I generally like "Du's Handbook of Classical Chinese Grammar," but one thing I do not like is when there is no explanation for a particular translation, as was the case with the above sentence. What was the translation for 則 (칙), for example? The following is what I believe to be a more literal translation of the sentence:德何如則可以王矣?What kind of virtue [does one need] to be able to be a [true] king?
First, notice that my translation translates each character, except for 何如 (하여), which is a kind of idiom that was originally written as 如何 (여하) and literally means "like (如) what (何)." So, if you really want to be picky, an even more literal translation would be: "[As for] virtue, like what standard can be used for a king?"德何如則可以王矣?[As for] virtue (德), what kind of (何如) standard (則) can (可) be used (以) [for] a king (王矣)?
Second, notice that my translation is actually different from that in "Du's Handbook," which not only fails to translate 則 (칙) as "standard" (準則 - 준칙), but also fails to translate 以 (이) as "to use." It seems "Du's Handbook" translated 可以 (가이) together as "to be able to."
By the way, the above Chinese sentence originally came from "The Analects of Mencius," where the following sentence was the one just before it.
The 乎 (호) is essentially one of the Chinese question marks, so the sentence literally translates as follows: "There is nothing (無) to use (以) [as] a standard (則) [for] a king (王乎)?"無以則王乎?Is there nothing (無) to use (以) [as] a standard (則) [for] a king (王乎)?
Finally, my translations above come from my own imagination. I wrote them because I question the original translations, which make little sense to me. For example, here is the translation of the above two sentences from my Korean version of "The Analects of Mencius":
無以則王乎?그만두지 (以) 않겠다면 (無) 곧 (則) 왕 노릇하기에 (王) 관해서 어떨지요 (乎)?
I do not even want to try to translate what I see as awkward Korean translations, so I will just let you figure it out. They seem to be making the translations harder than they really are. Of course, it could be that my translations are goofball, considering that I have never seen anyone translate it the way I have. That means my translations are way outside the box. Nevertheless, I'll let you decide which to use.德何如則可以王矣?어떻게 (何如) 수양하면 (德) 곧 (則) 덕행으로 (以) 왕 노릇할 수 있은 것 (可王) 인가 (矣)?