单项选择题

The machine can't be perfected overnight; in fact, it should be improved ______ .

A．one after another
B．by turn
C．fight away
D．step by step
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单项选择题
A lot of people have tried, but ______ have succeeded.
A．the few
B．a few
C．some
D．few
单项选择题
______ the importance of wearing seat belts while driving.
A．Little they realize
B．They little do realize
C．Little realize do they
D．Little do they realize
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