1、 Smoke particles and other air pollutants are often trapped in the atmosphere, thus forming smog.
    A.caught
    B.burned
    C.dirtied
    D.covered
    2、Apple trees need moisture in order to thrive.
    A.flower
    B.flourish
    C.pollinate
    D.bend
    3、 Her behavior is extremely childish.
    A.simple
    B.immature
    C.beautiful
    D.pretty
    4、 The Klondike was the scene of one of the biggest gold rushes the world has ever known.
    A.location
    B.view
    C.even
    D.landscape
    5、 The flower bud of a water lily opens at sunset since its opening is triggered by the decreased light.
    A.alleviated
    B.endured
    C.set off
    D.covered up
    6、 Tryouts for community orchestras are frequently judged by committees.
    A.Advertisements
    B.Auditions
    C.Performances
    D.Novelties
    7、 We have ample money for the journey.
    A.some
    B.little
    C.extra
    D.enough
    8、 You must try to wipe out the memory of these horrible events.
    A.strange
    B.terrible
    C.unusual
    D.unfair
    9、 Europeans established permanent colonies on the eastern shores of what is now the United States throughout the seventeenth century.
    A.during
    B.before
    C.up until
    D.just after
    10、 Mary gets up at the same time every morning.
    A.arises
    B.raises
    C.arrives
    D.stands up
    11、 Hundreds of buildings were wrecked by the earthquake.
    A.shaken
    B.damaged
    C.fallen
    D.jumped
    12、 A good employer gives hints to his or her employees without interfering with thei r creativity.
    A.freedom
    B.assistance
    C.clues
    D.funds
    13、 Mary called me up very late last night.
    A.shouted at me
    B.visited me
    C.telephoned me
    D.waked me
    14、 Every year each household in the United States discards approximately a ton oftrash.
    A.filler
    B.garbage
    C.paper
    D.fuel
    15、 The rainfall of the Hawaiian Islands varies tremendously according to their topography and orientation to the prevailing winds.
    A.seasonably
    B.surprisingly
    C.greatly
    D.inversely