It was the first time that a Canadian ________ a gold medal in a Winter Olympics . [ ]

A. won  

B. has won

C. had won  

D. was winning

关于显像时间的叙述，错误的是

A．肾动态显像每30～60s采集10帧

B．肝胆动态显像每5～15min采集1帧

C．心脏首次通过显像每50ms左右采集1帧

D．显像剂在体内运转较慢时，采集的速度要慢

E．显像剂在体内运转速度快，采集的时间间隔应短