It's quite warm here; we ________ turn the heating on yet . [ ]

A. couldn't  

B. mustn't

C. needn't  

D. wouldn't

患者心电图表现为心室律绝对规则，心率200次/分，QRS波宽大畸形，逆行P’波位于QRS波群之前，诊断首先考虑（）

A.室性心动过速

B.顺向型房室折返性心动过速

C.逆向型房室折返性心动过速

D.慢-快型房室结内折返性心动过速

E.快-慢型房室结内折返性心动过速