急性乙型肝炎窗口期可检出的血清标志物是（）

A.HBsAg

B.抗-HBs

C.HBeAg

D.抗-HBc

E.抗-HCV

If I________everything about Picasso already，I wouldn’t have to read the book.[ ]

A．know  

B．knew  

C．had known  

D．have known