This is the case in dance classes, where learning the content requires a teacher. They learn in an experiential way, by observing the teacher and being corrected as they perform the same movements. The teacher is distinct from the content. The teacher delivers a lecture based on cursory notes. The delivery can be largely extemporaneous, and ranges from formal content to comments on its validity and usefulness.
Content is provided by a textbook.
The situation in which the textbook is simply read to students verbatim probably is very rare, but I have seen it happen. At any rate, it represents such poor teaching that it does not merit further discussion. The example of the dance class was included for completeness. But with the exception of the apprenticeship approach used in training graduate students, few of us do this sort of thing. Perhaps science teachers would benefit from thinking about how they would teach dance or music.