I saw a woman running toward me in the dark.  Before I could recognize who she was,she had run

back in the  direction_____ she had come.   [ ]

A. of which        

B. by which        

C.  in which          

D. from which

男，52岁，下肢浅静脉明显曲张6个月，检查：大腿根部扎一止血带，嘱患者快速用 力屈伸膝关节20次，此时浅静脉曲张更加明显，提示

A．大隐静脉瓣膜闭锁不全
B．小隐静脉瓣膜闭锁不全
C．交通支静脉瓣膜闭锁不全
D．下肢深静脉有阻塞