一幢楼房20层高,相邻两层有15级台阶,某人从1层到20层,要走______级台阶.
15×(20-1),
=15×19,
=285(级).
答:要走285级台阶.
故答案为:285.
(2013·泉州一中期末)Close the door of fear behind you,and you ________ the door of faith open before you.
A.saw
B.have seen
C.will see
D.are seeing
微粒栓塞术主要用于()
A.脊膜动静脉瘘
B.脊髓AVM
C.脑膜瘤术前栓塞
D.头面部AVM
E.动脉瘤