15. It is requested that each of the teachers invited ______ a performance at the. party.
. We decided to turn to ___ can help us out.
. --- What do you think made Mary so upset? --- __ her new bicycle.
. They ___ out because the light’s on. Let’s go upstairs and have a look.
. I think ___ necessary ___ a foreign language.
. At the meeting I suggested that every class ___ divided into eight groups.