—I'm worrying about the coming examination.I'm afraid I cannot pass it.
—________!I'm sure you'll make it.
A:Go ahead
B:Good luck
C:No problem
D:Don't lose heart
小明同学设计实验如下:把盆栽植物放在黑暗处一昼夜后,选一叶片用黑纸片将B处两面遮盖,光照一段时间后摘下该叶片,用酒精脱去叶绿素,滴上碘液.请分析回答问题:
已知a,b都是负实数,则aa+2b+ba+b的最小值是( )