单项选择题

Animal migration is a seasonal or periodic movement of animals in response to changes in climate or food ______, or to ensure reproduction.

A．alternation
B．availability
C．utilization
D．capacity
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单项选择题
No hero of ancient or modern times can surpass the Indian with his lofty contempt of death and the ______ with which he sustained the cruelest afflication.
A．assent
B．fortitude
C．concern
D．reverance
单项选择题
The economy in this region has been stagnant for a long time and no signs of recovery have ______ till now.
A．shown up
B．kept up
C．picked up
D．made for
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