单项选择题

The primitive weapon ______ from that country as it could not be traced back to any other origin.

A．must be introduced
B．must have been introduced
C．might be introduced
D．might have been introduced
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单项选择题
She speaks as though she ______ on the spot.
A．was
B．were
C．had been
D．is
单项选择题
The project should be ______ in accordance with the latest estimate of the cost.
A．modified
B．filed
C．sponsored
D．retreated
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