No matter where he is,he makes ________ a rule to go for a walk before breakfast.(2012·陕西)
--- ______ 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, ______?
I hope she gives up her job ______ it makes her crazy.