We should consider the students’ request _____the school library provide more books on popular science.
Mary went to the box office at lunch time, but all the tickets ____out.
Four Chinese models were ______ the 14 people awarded prizes on Friday at the World Supermodel Competition.
I told you that you shouldn’t waste your time playing the computer games, ______?
--- ______ was it ______ they discovered the entrance to the underground palace? --- Totally by chance.
--- Some people believe that robots will take over the world one day. --- What if that is the ______?