男性,55岁,头痛1年余,2个小时前突然出现剧烈头痛,MRI检查如图所示,最可能的诊断为()
A.垂体瘤
B.脑膜瘤
C.颅咽管瘤
D.垂体瘤并卒中
E.动脉瘤
参考答案:D
将棱长为3的正四面体以各顶点截去四个棱长为1的小正四面体(使截面平行于底面),所得几何体的表面积为______.
—Where are my ruler and sharpener?
—_______ in your desk. [ ]
A. They is
B. It's
C. These are
D. They're