用一个平面截长方体、五棱柱、圆柱和圆锥,不能截出三角形的是( )。
圆柱
When the thief found the police had already __________ him, he ran away quickly.[ ]
A. realized
B. known
C. spotted
D. stared
()以上的混凝土称为高强混凝土。
A.C70
B.C60
C.C50
D.C40