30. The mayor of Beijing says that all construction work for the Beijing Olympics ______by the end of this month.
—Are there any tickets left? —Sorry. There are ________, if ________.
—What should I wear for the party?—It’s an informal one; it doesn’t matter ____ you’re dressed.
Recognized as ________ world cultural heritage by the United Nations in 2002, paper cutting is ________ practice which originated in ancient China.
After the war, a new school building was put up ________ there had once been a theatre.
Customers should learn to ________ advertisements so as not to be misled by them.