— Must I return the book this morning?
— No, you ______. But you ______ return it before supper.
A:needn't; must
B:mustn't; can
C:mustn't; may
D:can't; need
若log2x=3,则x=( )
现实生活中,我们会遇到各种各样的“标志线”。下列属于关爱公民生命健康权的“标志线”是()①横穿马路的“斑马线” ②施工现场的“警戒线” ③银行窗口的“l米线” ④火车站台的“候车线”
已知a>1,则limx→01-ax2+3ax=( )