More and more high-rise buildings have been built in big cities ________ space.

A. in search of        B. in place of      C for lack of          D. in memory of

患者女性，55岁，行ECG检查示：P波消失，代之是400次／分左右的F波，QRS波形态正常，QRS波群间隔绝对不规则，心室率通常在每分钟110次，从心电图可诊断 （）

A.房扑

B.室扑

C.房颤

D.室上速

E.室速