鉴别尿路感染与 * * 综合征的最根本点是（）。

A.尿白细胞的多少

B.尿红细胞的多少

C.尿白细胞管型的有无

D.真性细菌尿的有无

E.尿路刺激症状的有无

I've been writing this report ________ for the last two weeks, but it has to be handed in tomorrow.[    ]

A. finally  

B. immediately

C. occasionally  

D. certainly