please insert a u3 smart drive and run u3 customizer again

please insert a U3 smart drive and run U3 Customizer please insert a u3 smart drive and run u3 customizer again please insert a U3 smart drive you need 14.9mb of free space on your u3 smart drive to perf U3,A.3a please insert disc and try again 求文档:you can't usr your u3 smart deive forbackup,please defin Please insert FF7game Disc 1,2or3 and try again. 英语翻译U3 section A,2a 英语初三6A U3 练习题 点击那个后出现 Setup not found,please insert Disc 2 and try again 诶 U1,U2,U3是什么意思?