女性，32岁。因不明原因发热2周来院门诊。体检：心脏有杂音。拟诊感染性心内膜炎入院

为明确诊断抽血培养的最佳时间是（）

A.先用抗生素3d，体温不退时抽取

B.停用原用的抗生素2d后，抽取3-5次血培养

C.在抗生素应用前，在24小时中，于畏寒发热时抽3次血培养

D.原先抗生素可继续应用，抽取3次血培养

E.停用抗生素1～2周后抽取血培养3次

How many minutes will it take to completely fill a water tank with a capacity of 3,750 cubic feet if the water is being pumped into the tank at the rate of 800 cubic feet per minute and is being drained out of the tank at the rate of 300 cubic feet per minute

A．3 min. 36 see.

B．6 minutes

C．7 min. 30 sec.

D．8 minutes

E．(E) 1,875 minutes