—Tony, I really appreciate your wonderful performance in the concert．

—_________．

A．I've practiced for ages

B．Well, it's just so-so

C．No, I don't think so

D．Thank you very much

突发事件的特点有（）。

A.突发性

B.可预期性

C.群体性

D.社会的影响性

E.利益的矛盾性