Don't worry. Your package ____ (keep) here until you come back, so enjoy shopping here.
y=cosx经过伸缩变换x'=2xy'=3y 后,曲线方程变为( )
用日心说否定了影响人类达千年之久的托勒密地心说,有力地推动了人类文明的科学家是( )
下列血管中流动着动脉血的是( )