24 Advances in spoken discourse analysis
Follow-up, the third class of move in teaching exchanges, is an interesting
category. Its function is to let the pupil know how well he/she has performed.
It is very significant that follow-up occurs not only after a pupil answering
move, but also after a pupil opening move when the head is realized by
an informative. In other words the teacher often indicates the value of an
unelicited contribution from a pupil, usually in terms of relevance to the
discourse.
Follow-up has a three-term structure, pre-head, head, post-head, realized
by accept, evaluate, and comment respectively.
The act evaluate is seen by all participants as a compulsory element. A
teacher can produce a follow-up move which overtly consists of only accept
or comment, but evaluation is then implicit (and usually unfavourable).