24．—You shall get an iPhone as long as you come out first in the contest．

—Is that a ____? Don't let me down, I hope．

A．trick

B．decision

C．promise

D．Goal

二尖瓣狭窄患者最常见的早期症状为

A．阵发性夜间呼吸困难

B．劳力性呼吸困难

C．端坐呼吸

D．声音嘶哑

E．咯血