________ is known to us all is that the
题型：选择题
问题：
________ is known to us all is that the old worker，for ________ life was hard in the past，still works hard in his seventies.
A．As；whom
B．What；whose
C．It；whose
D．What；whom
________ is known to us all is that the old worker，for ________ life was hard in the past，still works hard in his seventies.
A．As；whom
B．What；whose
C．It；whose
D．What；whom