主动脉瓣关闭不全的体征有（）
A.听到S3
B.心尖区S1亢进
C.A2减弱或消失
D.心尖区低调柔和的舒张中期杂音
E.脉压变小
参考答案：A, C, D
Hillary Clinton arrived in Beijing yesterday, ________the start of her short visit to China. [ ]
A. marked
B. having marked
C. marking
D. to mark
门窗工程应对建筑外墙的金属门窗、塑料门窗进行“三性”复验。
