My new pen __________.Who __________ have taken it?
Catherine, ____ the alarm clock for 6 o’clock, or you would oversleep and be late for the train.
The results of the examination ________ that you have all made great progress.
--- Is your brother going to Jack’s birthday party tonight? ---I am not sure. He __________ go to a concert with his girlfriend instead.
It took a long time for the effective use of natural gas_________.
At the beginning of the 20th century, many people thought that the family was falling apart--- _______, they thought it was dying.