Rio De Jeneiro has won the right to host the 2016 Olympic Games, and the Brazilians will be occupied in building stadiums .
They _____ be at home. You see, the door is locked from the outside.
______ you return those books to the library immediately, you will have to pay a fine.
The teacher began by _____ us where the city was and went on ______ about its history.
Human be haviour is mostly a product of learning, ____ the behavior of animals depends mainly on instinct.
_______ from the hill, the whole city of Nanjing looks more beautiful.