—Hello!May I speak to Mary？—Yes.（）Mary，you are wanted on the phone.

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().

A.充要条件
B.必要条件
C.无关条件
D.充分条件

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—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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