来自潘爱先的问题
【____weallknowis____theoldlady，thoughsheisveryrich，stillworkseveryday．（）A.As；thatB.What；thatC.It；whatD.That；why】
____ we all know is ____ the old lady，though she is very rich，still works every day．（）
A.As； that
B.What； that
C.It； what
D.That； why
