1)...the one hand,it is a very difficuult problem, but the other hand,it  is very interesting.
2)Tomorrow we can begin exploring ... this charming corner of Italy.
3)His words prevented us ... coming.
4)We are looking forward ... meeting you all again,next summer.
5)I blamed my cousin ... telling lies.
6)Jane succeeded ... writing compositions really well.
7)I am used ... doing morning exercises.