Those experienced doctors in our country _______the meeting in order to find out the real_______ of bird flu(禽流感)

He took the machine to pieces to find out how it .

The commercial city, Loulan, used to be a stopping point on the silk road between the West and the East, ______ by sandstorms from AD200 to AD 400.

Mrs. Smith, do you think it is wise for you to give your children ______ they want? — No, that is ____ I am mistaken.

Catherine wasn’t sure if the album was the right one, but she bought it 　　　　.