A:—Is this a ruler? —Yes.
B:—Is this a ruler? —No.
关于20世纪80年代以来,我国人口迁移的正确叙述是 ( )
——What do you want to be when you graduate from middle school?——I want to be _________university student. I'm in great ______ need of knowledge.
不等式3x-12-x的解集是( )