主燃期后段的特点是什么？
参考答案：主燃期后段燃烧产物增多，氧气量减少，高温缺氧是主燃期后段的特点。
Are you going to the football game?
— No, the tickets are ________ for me.
A．too much high
B．so much expensive
C．far too expensive
D．highly expensive
比较均数相差悬殊的几组资料的变异度时可用（）
A.变异系数
B.极差
C.方差
D.标准差
E.偏倚
Are you going to the football game?