单项选择题

They repeated the experiment several times ______ they were sure that the result was reliable.

A．until
B．for
C．since
D．when
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单项选择题
It was not until bedtime ______ he hurried back to the dormitory.
A．when
B．unless
C．that
D．which
单项选择题
When people get unemployed, what is often worse than lack of wages is______.
A．poverty
B．laziness
C．idleness
D．inability
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