阿司匹林用于心绞痛缓解期治疗的作用原理是

A．减慢心率、降低心肌收缩力、减少心肌耗氧量
B．通过抑制钙离子进入冠脉、周围血管壁平滑肌细胞内而扩张冠脉及周围血管
C．抑制血小板聚集
D．改善心肌营养与代谢
E．扩张冠脉及外周血管，减轻心脏负担

— Jack has spent an hour in the shoe shop．Hasn't he decided which pair of shoes to buy?

— Maybe．Young as he is, he is         about his appearance．

A．special

B．curious

C．particular

D．confident