—Where are my ruler and sharpener?

—_______ in your desk. [ ]

A. They is

B. It's

C. These are

D. They're

女，30岁，发热3天，晕厥1次，心电图显示三度房室传导阻滞，心室率40次/分，下列各例治疗应首选（）。

A．临时心脏起搏器植入 

B．肾上腺素 

C．直流电复律 

D．毛花苷丙（西地兰） 

E．阿托晶