借____ 错____ 浑____ 挥____ 桥____ 骄____
盼____ 份____ 被____ 披____ 航____ 船____
粮____ 狼____ 精____ 清____ 蓝____ 篮____
像____ 象____ 递____ 弟____ 洗____ 先____
咏____ 永____ 抢____ 仓____ 芽____ 牙____
He was told ____ (drive) carefully.
解决危机,可以效仿别人的具体方法。( )
已知抛物线y=ax2+bx+c,如图所示,直线x=﹣1是其对称轴,
(1)确定a,b,c,△=b2﹣4ac的符号;
(2)求证:a﹣b+c>0;
(3)当x取何值时,y>0,当x取何值时y<0.