某超市对今年前两个季度每月销售总量进行统计,为了更清楚地看出销售总量的总趋势是上升还是下降,应选用____ 统计图来描述数据.
若cosα+sinα=-13,则sin2α=( )
已知:a5=b7=c8,且3a﹣2b+c=9,则2a+4b﹣3c=____
-I think _______ask Tim for some advice. -_______. Last time when I turned to him, he refused to help.