用适当的介词填空

（1）The Hope Project has built many schools ____ big classrooms and libraries.

（2）Paris is ____ the largest cities in the world.

（3）I regard you ____ my best friend.

（4）No one can be successful ____ hard work.

（5）Did you see an old tree across ____ the old house?

（6）We can't pass the exam ____we study hard.

（7）Could you tell me something interesting ____ the old man?

（8）The young girl has been to ten countries ____ five years ago.