-How did you go home after the party last night?

-Well,there were no buses________we had to walk.[ ]

A．so as to  

B．in order to

C．so that  

D．in order that

关于动态空间重建扫描仪的描述，错误的是

A．动态空间重建扫描仪的开发应用始于1975年
B．目的是使该装置仅做运动器官(如心、肺)的成像
C．目前的动态空间重建扫描时间是10ms，最快可达30层/s
D．纵向和横向分辨力为1mm
E．是一种动态的容积扫描