已知一次函数y=kx+b,当0≤x≤2时,对应的函数值y的取值范围是-2≤y≤4,则kb的值为[ ]
A.12
B.-6
C.-6或-12
D.6或12
答案:C
That was really a splendid evening. It's years ______I enjoyed myself so much.
A.when
B.that
C.before
D.since
表生产相同产品的甲乙两企业2009年的主要经济指标,由下表可知 [ ]
A.甲的利润低于乙
B.甲的劳动生产率低于乙
C.甲的经济效益高于乙
D.甲的个别劳动时间多于乙