地球上极昼、极夜现象出现的范围是（ ） A．北极圈以北和南极圈以南的地区 B．南

I helped the blind man       the bridge.[ ]

A. crossing    

B. go through  

C. go across  

D. go cross

—Did you watch that Korean TV series last night?  

—Yes, but it was not until eleven o'clock ______ the play started[ ]

A. that  

B. which  

C. in which  

D. as

_____ she was no more than twenty-two, she was already a highly successful business- woman.[      ]

A. Though      

B. Once        

C. Because        

D. Since

治疗带下过多的常用方剂有

A．易黄汤

B．左归丸

C．内补丸

D．知柏地黄汤

E．六味地黄汤

关于去甲肾上腺素下列哪项正确（）

A.对α受体的作用较β受体作用显著

B.只引起动脉血管收缩，对静脉血管不影响

C.对β受体作用较α受体作用显著

D.对肺血管呈舒张作用

E.不增强心肌耗氧