单项选择题

Many different animals may be taught to do some simple jobs if______.

A．they have enough food to eat
B．they learn they will get something to eat in return after doing them
C．they are sent to school
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单项选择题
The story happened in______.
A．England
B．America
C．Germany
单项选择题
We can infer(推断) that
A．people there hadn't seen Einstein before
B．people liked the driver more than Einstein himself
C．people knew Einstein very well
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