Although ________ after the Civil War, the American blacks still took no important role in the white Americans except as servants and laborers.
The room is very large and only little room _____ by the new piano.
The task was very hard, so _____ were needed.
The college entrance examination is coming, the students are _____ it.
This is the school _____ they visited last year and is the one _____ my father once worked.
The enemy troop suddenly took the small village by surprise _____ a rainy morning.