马戏团的小丑有红、黄、蓝三顶帽子和黑、白两双鞋,他每次演出时都要戴一顶帽子,穿一双鞋。小丑的帽子和鞋共有多少种搭配方法?[ ]
A.9
B.6
C.3
D.15
答案:B
The government claims that the economy is improving, but this survey suggests ______. [ ]
A. moreover
B. therefore
C. otherwise
D. meanwhile
飞行管理系统的显示装置是:().
A.MCP(方式控制板)
B.VOR控制板
C.CDU
D.EFIS控制板