脊髓炎与硬脊膜外脓肿的鉴别要点（）。

A.脊柱有无压痛

B.脑脊液有无炎性改变

C.椎管内有无梗阻

D.有无脓毒血症的临床表现

E.起病是否急剧

       I’ve been working all day, but I feel as if I _______ nothing.

A．have been achieved

B．were achieving

C．had achieved

D．am achieving