采样单元煤量少于1000t的汽车装载原煤,其最少子样数是()个。
A、30
B、18
C、10
参考答案:B
定义符号yx表示与自变量x所对应的函数值.例如对于函数y=x2-2x+4,当x=2时,对应的函数值y=4,则可以写为:y2=4.在二次函数y=ax2+bx+c(a>0)中,若yt+1=y-t+1对任意实数t都成立,那么下列结论错误的是( )
A.y0=y2
B.y-1>y1
C.y4<y3
D.y2>y1
I hardly know anyone in the villiage________William and you.
A.besides
B.apart from
C.except for
D.including