Given the Question and Answer pair, detect whether the answer is acceptable or not. Denote acceptable answer as "yes", otherwise denote as "no". An acceptable answer is consistent with the context in question, detailed, long, and uses general knowledge of English. Answers that are not definite and suggest a variety of options are not acceptable answers.

[Q]: Question: Do the English have an ancient (obsolete) verb for the action of the book opening? For example, in Russian we say otkrit' (open the book), but in the Old slavonic the verb razognuti (to unbend the book) was used. 
Answer: The Middle English verb undon was often applied to opening a book (and many other objects). c1300 SLeg.Fran.(1) (LdMisc 108)159 : He on-dude e bok and e furste at he cam to at was a godspel. (He undid the book and the first that he came to - that was a gospel.) a1325 SLeg.(Corp-C 145)354/166 : Hewende him sulf for is wei & e oer vndude e bok. (He walked himself forth his way and the other undid the book.) c1475 Mankind (Folg V.a.354)797 : All e bokys in e worlde, yf ei hade be wndon, Kowde not a cownselde ws bett. (All the books in the world, if they had been undone, could not have counseled us better.) This meaning has since disappeared along with the book clasps that would have once been common on books. (To see a few examples of bindings, see "Medieval bindings" on the British Library site.).
[A]: no


[Q]: Question: Someone told me that I shouldn't use the phrase discuss about, but should say, instead, discuss (the topic). He said discuss means talk about and using discuss about is like saying talk about about, which is redundant. Is he correct? Could somebody elaborate on this? 
Answer: Your friend is correct. You can discuss something, or you can talk about it, but discuss about is redundant for the reason you identified. discuss: to speak with another or others about But if you want to use the word about, you can have a conversation about, confer about, debate about, or even have a powwow about. Most of the other synonyms for discuss don't take about, nor is it needed to converse (or debate).
[A]: yes


[Q]: Question: What's the difference in meaning between "register" and "registry"? Can both be used interchangeably when talking about an official (public) list of items, records? 
Answer: Registry is a place of registration or a book or list in which registration is made. Registration is the act of registration, so a registration number is a number under which something such as a company or a person is registered. A registry number, however, is the number given to a place of registration or a book or list of registration, since too many of them may be around, but that number is not large, say, in five digits mostly because there are only a limited number of registration places or books or lists that are in existence for every particular purpose while a registration number involving companies, items, goods or persons may be as large as 16 digits and more and may comprise from letters and digits both, because there a great many numbers of those items or companies or persons who are registered.
[A]:
no