①在困难面前不低头不丧气 ②勇于开拓,积极进取
③志存高远,执著追求 ④得过且过,懒惰成性
A:①③④
B:②③④
C:①②④
D:①②③
— Mike, who helped make the paper plane?
— Nobody! I made it all by myself.
方程|2x﹣4|=0的解是( )
计算2m2m+n-m-nn+2m的结果是( )