The outbreak of this incident has given us much for thought, forcing us to ______ seriously on the past and the future.
________ one of you breaks the window will have to pay for it.
________ makes the book so extraordinary is the creative imagination of the writer.
No one ________ the building without the permission of the policeman.
We usually take turns ________ some cleaning, and today it is my turn ________ it.
Seeing the bad results of the exams, she was rather frustrated and felt _________ about her future.