________ at the theatre, he found the ticket his friend gave him was left at home. [ ]

A. To arrive  

B. On arriving

C. While arrived  

D. On arrived

以下不属实喘特征的是（）

A.发作急骤

B.呼吸深长

C.息粗声高

D.动则喘甚

E.呼出为快