2.
11/ Have the winners of the contest already been interviewed? - Yes.
12/ When will the programme be repeated? - next week.
13/ How are the students tested? - very seriously.
14/ By whom was the bridge destroyed? - by the flood.
15/ When must the machine be installed? - as soon as possible.
3.
16/ of
17/ ----
18/ for
19/ with
20/ about
21/ from
22/ into
23/ on.