____ was it _____they discovered the entrance to the underground palace?— Totally by chance.

32．Customers are asked to make sure that they_____ the right change before leaving the shop

They don’t study in No 1 High School, ___ those boys.

more energy to my study instead of being addicted to Internet games, I would be sitting in a comfortable office now.

Is Richard still living here—No,he to Paris already.