Only after Helen moved to Australia ______ how important she was to me .

A．I had realized

B．had I realized

C．I did realize

D．did I realize

为了减少油墨及溶剂对压印滚筒的影响，须注意（）。

A.钢管壁厚的控制

B.动，静平衡的处理

C.印刷基材与压印滚筒在规矩上的配套

D.油墨等杂质要及时擦拭干净