He worked late into the night yesterday. That’s ___ he couldn't get up on time this morning

A．how

B．why

C．what

D．when

腹部CT扫描技术不包括

A．常规为患者仰卧，头先进
B．定位像为正位像
C．肝脏和脾脏以膈顶为扫描基线
D．腹膜后腔以肾门为扫描基线
E．肾和肾上腺以肾上极为扫描基线