We use nor after a negative statement to show that what has already been said is also true for the person or situation in the statement beginning with nor: "I'm not English and nor is John", ie I'm not English and John is also not English; "-They don't speak French" "-Nor do they speak German", ie it is also true that they don't speak German. Alternatively, we could say: They don't speak German either.
We use nor at the beginning of a clause and then we put the verb in the same form as we would ask a question, ie first the auxiliary verb (or the main verb if there is no auxiliary), then the subject (and you stop here if it's a short answer) and then the main verb (if an auxiliary has been used). Examples: Nor am I/are you/is he,she,it/are we,you,they/do I,you,we,they/have I,you,they/has he,she,it/can I etc. etc.
We can use neither instead of nor in the above cases.
Another use of nor (together with neither, which comes first) in negative sentences is to say that the same thing is true for two persons or in two situations: Neither John nor Mary are happy: this means that both John and Mary are unhappy. We neither saw nor heard anything: this means that we did not see and we did not hear anything.
In the above case we cannot use neither instead of nor.
Nor requires inversion as do little, hardly, no sooner...than, never, not only, not, .... and, in general most restrictive, limiting or negative expressions placed at the beginning of a sentence/clause. And now, can anybody tell me how I can check whether the answer is ok or this is just to put our knowledge to test and leaving us like this... feeling we 'may' be right.