采购发票是供应商开出的销售货物的凭证，系统根据采购发票确认采购成本，并据以登记应付账款。
参考答案：对
Some White House staff were ______ that the president was no longer in control.
A．talking
B．whispering
C．speaking
D．telling
测定炉顶空间温度应在结焦时章的三分之二时进行
