11.   My knees appeared and disappeared in the mists rising from the tub.

12.   Planes have occasionally disappeared in midair, but this is a rare phenomenon.

13.   She got up waveringly, disappearing in the nebulous direction in which the cowgirl had gone.

14.   That ship had suddenly disappeared in placid waters without trace.

15.   The dragon disappeared in a puff of smoke.

16.   The last vestiges of serfdom had disappeared in the sixteenth century, and the peasants farmed the land as leaseholders or sharecroppers.

17.   The scars will disappear in a year or two.

18.   The ship had suddenly disappeared in calm waters.

19.   Then he turned his car around in the frozen street and disappeared in a cloud of vapor from the exhaust.