1) It is impossible _for__ elephants to fly.
2) My parents introduced me __to_ their guests.
3) We have two good seats __in_ the stalls.
4) The audience laughed and applauded _to__ the actors.
5) His answer impressed ______ me.
6) We bought a new TV-set _at__ half price.
7) Do you think John will agree _to_ the plan?
8) You should pay attention __to__ what your teacher says.
9) My uncle graduated __from__ Oxford in 2014.
10) The story was based _on__ real life.