It was not until then that I came to know that knowledge _______ only from practice.

A．had come

B．has come

C．came

D．comes

以下哪种CT表现更倾向于硬膜外血肿而不是硬膜下血肿（）

A.血肿为等密度

B.血肿不超越颅缝

C.血肿不超过中线

D.边缘清楚

E.占位效应更重