若(x)在[a,b]上连续的函数,则a)f(b)<0是f(x)在(ab)内取零值的().

—Would you mind if I played the violin here？—（）.

A.Yes，I don’t mind
B.Yes，do as you please
C.No，you won’t
D.No，do as you please

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偶极子极化()。

A.所需时间短
B.在频率很高时极化
C.属弹性极化
D.与温度的加强关系很大

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