下列关于统计总体、个体和样本概念的说法中，错误的是( )。 A．统计中通常把所要研

--- Jane, ________________________

--- A policeman.

A．how is your brother?

B．what does your brother do?

C．where is your brother?

D．how old is you brother?

男，51岁，胸骨后剧烈疼痛4小时，伴大汗淋漓，血压80/40mmHg，心率134次/分，面色苍白，四肢发冷，心电图提示广泛心肌梗死。

该患者最理想有效治疗措施是（）。

A.毛花苷C强心

B.多巴胺升压

C.尿激酶溶栓

D.主动脉内球囊反搏泵

E.直接PTCA术

三极管工作在饱和区时，两个PN结的偏量是：发射结加正向电压，集电极加正向电压。

折点加氯

A METHOD OF TOWING VESSELS THROUGH POLAR ICE BY MEANS OF ICEBREAKING TUGS WITH A SPECIAL STERN NOTCH SUITED TO RECEIVE AND HOLD THE BOW OF THE VESSEL TO BE TOWED defines（）.

A.Towing operations

B.Rigid coupled towing

C.Close coupled towing

D.Hard coupled towing