It is dangerous to __________ in the forest,because you are easily lost.
--Did you telephone the manager’s office? ---Yes.He ____ back before 9 this morning.
--Do you remember ____ he came? --Yes, I do.He came by car.
He ____ his home for a week.
--What’s ___ population of China? --China has ____ population of 1.5 billion.
--what do you think of the film? ---_____?