单项选择题

It is true that there are still abundant reserves of metals which have not yet been______, but it is necessary to take steps to ensure that alternative materials are substituted whenever possible.

A．utilized
B．mobilized
C．acquired
D．cultivated
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单项选择题
Prior to our conference, the executive director had requested that everyone______ well prepared.
A．is
B．be
C．was
D．will be
单项选择题
The bond of true affection had pulled us six very different men from six very different countries across Antarctica; we proved in the end that we weren't very different______.
A．for all
B．as usual
C．after all
D．in particular
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