颅内动静脉畸形CT平扫,一般可为高、等、低三种密度。低密度是指()
A.胶质增生
B.尚未钙化的血栓
C.梗死区及脑萎缩的脑脊液充填区
D.周围水肿
E.脑实质
参考答案:C
对于曳引与强制驱动电梯的定期检验报告,检验机构和使用单位应当至少保存()个检验周期。
A.2
B.3
C.4
D.5
The young couple was worried,because neither of them was aware ______ they had lost the necklace.
A.of the place
B.of which
C.where
D.of where