单项选择题

In manufacturing, cheaper materials are constantly being ______ for the better and more expensive kind.

A．replaced
B．transformed
C．displaced
D．substituted
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The emergency ______ reserves of energy she did not know she possessed.
A．called for
B．called on
C．called forth
D．called down
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He was ______ admittance to the concert hall for not being properly dressed.
A．rejected
B．denied
C．withheld
D．deprived
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