19. Which do you enjoy ______ you weekend, doing sports or watching TV?
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 ______?
______, Jack couldn’t get the door open. He had to dial 110.
I think that he must be looking up the information in the library, ______?