You raise a very relevant issue, one I’d been wondering about for a long time. For an adaptation to be considered a different work (the word “derivative”, being closely related to US law, is not part of CC license code since version 4.0), a minimal amount of “originality” is required. The originality threshold varies among jurisdictions, but I don’t think reproducing verbatim a specific part (a whole section, for instance) would qualify; same for simple basic reformatting. On the other hand, multiple excerpts carefully chosen to form a kind of summary could.

The derivative-or-not issue notwithstanding, before version 4.0, the licence code of NC licenses was ambiguous, in my opinion, as to the requirement of reproducing the work in its entirety. Curiously, I’ve not seen much discussion on this issue, in contrast to, say, the NC condition.

Now I believe things are much clearer: the code of NC 4.0 licenses sates: “… a worldwide, royalty-free, non-sublicensable, non-exclusive, irrevocable license to exercise the Licensed Rights in the Licensed Material to … A. reproduce and Share the Licensed Material, in whole or *in part*” (my emphasis). Previous versions spoke only of “Reproducing the Work”.