21.Care should be taken to decrease the length of time that one is _____ loud continuous noise.
A.subjected to
B.filled with
C.associated with
D.attached to
22.Careful surveys have indicated that as many as 50 percent of patients do not take drugs ______ directed.
A.like
B.so
C.which
D.as
23.Changing from solid to liquid, water takes in heat from all substances near it, and this ______ produces artificial cold surrounding it.
A.absorption
B.transition
C.consumption
D.interaction
24.Charles can't go to work today because he _____ a cold.
A.has
B.feels
C.takes
D.thinks
25.Charles has not the least ______ of giving up his research.
A.intention
B.decision
C.idea
D.hope
26.Columbus' decision to sail west to reach the East _____ on his belief that the earth was round.
A.existed
B.sat
C.relaxed
D.rested
27.Despite the wonderful acting and well-developed plot the _____ movie could not hold our attention.
A.three-hours
B.three-hour
C.three-hours'
D.three-hour's
28.Difficulties can _____ a person's best qualities.
A.bring up
B.bring out
C.bring about
D.bring to
29.Doctors sometimes _____ old cures when modern medicine doesn't work.
A.fall on
B.fall down on
C.fall back on
D.fall in upon
30.Does brain power _____ as we get older? Scientists now have some surprising answers.
A.descend
B.decline
C.deduce
D.collapse